A college basketball player makes 80% of his freethrows. Over the course of the season he will attempt 100 freethrows. Assuming free throw attempts are independent, the probability that the number of free throws he makes exceeds 80 is approximately:____________.
A) 0.2000
B) 0.2266
C) 0.5000
D) 0.7734

Answers

Answer 1

Answer:

The probability that the number of free throws he makes exceeds 80 is approximately 0.50

Step-by-step explanation:

According to the given data we have the following:

P(Make a Throw) = 0.80%

n=100

Binomial distribution:

mean:   np = 0.80*100= 80

hence, standard deviation=√np(1-p)=√80*0.20=4

Therefore, to calculate the probability that the number of free throws he makes exceeds 80 we would have to make the following calculation:

P(X>80)= 1- P(X<80)

You could calculate this value via a normal distributionapproximation:

P(Z<(80-80)/4)=1-P(Z<0)=1-50=0.50

The probability that the number of free throws he makes exceeds 80 is approximately 0.50

Answer 2

The probability that the number of free throws he makes exceeds 80 is approximately 0.5000.

Given that,

A college basketball player makes 80% of his free throws.

Over the course of the season, he will attempt 100 free throws.

Assuming free throw attempts are independent.

We have to determine,

The probability that the number of free throws he makes exceeds 80 is.

According to the question,

P(Make a Throw) = 80% = 0.80

number of free throws n = 100

Binomial distribution:

Mean: [tex]n \times p = 0.80 \times 100 = 80[/tex]

Then, The standard deviation is determined by using the formula;

[tex]= \sqrt{np(1-p)} \\\\=\sqrt{80\times (1-0.80)}\\\\= \sqrt{80 \times 0.20 } \\\\= \sqrt{16} \\\\= 4[/tex]

Therefore,

To calculate the probability that the number of free throws he makes exceeds 80 we would have to make the following calculation:

[tex]P(X>80)= 1- P(X<80)[/tex]

To calculate this value via a normal distribution approximation:

[tex]P(Z<\dfrac{80-80}{4})=1-P(Z<0)=1-0.50=0.5000[/tex]

Hence, The probability that the number of free throws he makes exceeds 80 is approximately 0.5000.

To know more about Probability click the link given below.

https://brainly.com/question/21586810


Related Questions

Evaluate 1/2 + 1/2 ÷ 18​

Answers

Answer:

1/18

Step-by-step explanation:

First you would add 1/2 and 1/2 to get 1 then you would divide it by 18 to get 1/18

Answer:

1/18

Step-by-step explanation:

plz mark me brainliest.

What’s the correct answer for this question?

Answers

Answer:

The last option is the correct choice 33.5

Step-by-step explanation:

[tex]V=\pi r^2\frac{h}{3} \\=\pi 2^2\frac{8}{3} \\=33.51\\=33.5[/tex]

Answer:

D

Step-by-step explanation:

In the attached file

Please help me HURRY!!!!!!

Answers

K=-2 because the other answers are greater than -2 and the answer has to be less than or equal to

Gravel is being dumped from a conveyor belt at a rate of 15 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. How fast is the height of the pile increasing when the pile is 12 ft high? (Round your answer to two decimal places.)

Answers

Answer:

0.13 ft/min

Step-by-step explanation:

We are given that

[tex]\frac{dV}{dt}=15ft^3/min[/tex]

We have to find the increasing rate of change of height of pile  when the pile is 12 ft high.

Let d be the diameter of pile

Height of pile=h

d=h

Radius of pile,r=[tex]\frac{d}{2}=\frac{h}{2}[/tex]

Volume of pile=[tex]\frac{1}{3}\pi r^2 h=\frac{1}{12}\pi h^3[/tex]

[tex]\frac{dV}{dt}=\frac{1}{4}\pi h^2\frac{dh}{dt}[/tex]

h=12 ft

Substitute the values

[tex]15=\frac{1}{4}\pi(12)^2\frac{dh}{dt}[/tex]

[tex]\frac{dh}{dt}=\frac{15\times 4}{\pi(12)^2}[/tex]

[tex]\frac{dh}{dt}=0.13ft/min[/tex]

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 460 seconds and a standard deviation of 40 seconds. Find the probability that a randomly selected boy in secondary school can run the mile in less than 368 seconds.

Answers

Answer:

The probability that a randomly selected boy in secondary school can run the mile in less than 368 seconds is P(X<368)=0.011.

Step-by-step explanation:

We have a normal distribution with mean 460 and standard deviation 40 to describe the time for the mile run in its secondary-school fitness test.

We have to calculate the probabiltiy that a randomly selected boy in secondary school can run the mile in less than 368 seconds.

To calculate this, we have to calculate the z-score for X=368:

[tex]z=\dfrac{X-\mu}{\sigma}=\dfrac{368-460}{40}=\dfrac{-92}{40}=-2.3[/tex]

Then, we can calculate the probability:

[tex]P(X<368)=P(z<-2.3)=0.011[/tex]

A tree casts an 8-foot shadow on the ground. The length from the tip of the shadow to the top of the tree is 17 feet. What is the height of the tree?

Answers

Answer:

Height of tree = 15 ft

Step-by-step explanation:

Given:

Length of shadow (Base) = 8 ft

Length from the tip to top of the tree (Hypotenues) = 17 ft

Find:

Height of tree = ?

Computation:

Using Pythagoras theorem:

[tex]Height\ of\ tree = \sqrt{Hypotenues^2 - base^2} \\\\Height\ of\ tree = \sqrt{17^2 - 8^2} \\\\Height\ of\ tree = \sqrt{289-64}\\\\Height\ of\ tree = \sqrt{225}\\\\ Height\ of\ tree =15[/tex]

Height of tree = 15 ft

Answer:

The answer is 15 feet from the ground to the top of the tree.

Step-by-step explanation:

A linear track begins at 0 meters and has a total distance of 100 meters to the finish line. Juliet starts at the 100 meter mark while practicing for a race. After running 45 meters how far is she from the beginning of the track?

Answers

Answer:

It’s D, 55.

Step-by-step explanation:

After running 45 meters, Juliet runs 55 meters from the beginning of the track

what value of x makes the equation true ? 9.68x + 21.6 -6.23x = 2.3x + 17​

Answers

Answer:

-4 please brainliest me

Step-by-step explanation:

9.68x+21.6-6.23x=2.3x+17

lets move it to the left

9.68x+21.6-6.23x-(2.3x+17)=0

Then, We add all the numbers together, and all the variables

3.45x-(2.3x+17)+21.6=0

We get rid of parentheses

3.45x-2.3x-17+21.6=0

We add all the numbers together, and all the variables

1.15x+4.6=0

We move all terms containing x to the left, all other terms to the right

1.15x=-4.6

x=-4.6/1.15

x=-4

x= -8 makes the equation true.

What is Equation?

Equations are mathematical statements with two algebraic expressions flanking the equals (=) sign on either side.

It demonstrates the equality of the relationship between the expressions printed on the left and right sides. LHS = RHS is a common mathematical formula.

Coefficients, variables, operators, constants, terms, expressions, and the equal to sign are some of the components of an equation. The "=" sign and terms on both sides must always be present when writing an equation.

Given:

9.68x + 21.6 -6.23x = 2.3x + 17​

Now, solving for x

9.68 x - 6.23x - 2.3x = 17 - 21.6

1.15x= -4.6

x= -4.6 / 1.15

x= -8

Hence, x= -8 makes the equation true.

Learn more about equation here:

https://brainly.com/question/10413253

#SPJ5

Which of the given shapes has a larger area?

Answers

Answer:

Rectangle

Step-by-step explanation:

Count the units. For the triangle, A=0.5bh. 0.5(4)(6)=A. A=12

Now, for the rectangle, A=bh. A=(3)(5). A=15. The rectangle is larger

The average score of all golfers for a particular course has a mean of 70 and a standard deviation of 3.5. Suppose 49 golfers played the course today. Find the probability that the average score of the 49 golfers exceeded 71.

Answers

i don’t know the answer to that sorry

help me................​

Answers

Answer:

x = 5. y = 4

Step-by-step explanation:

7x - 4 = 31

7x = 35

x = 5

4y + 8 = 24

4y = 16

y = 4

X=5/ y=4

7x-4=31. 4y+8=24
+4. +4. -8 -8
7x=35. 4y=16
/7 /7. /4. /4
X=5. Y=4

14 fewer than 12 times the
number of people in my
family is 46.

Answers

Answer:

538

Step-by-step explanation:

12 times 46 is 552 then 552 minus 14 is 538

:D

FIND P(NOT 6) WHEN YOU ROLL A STANDARD NUMBER CUBE THEN DESCRIBE THE LIKELIHOOD OF THE EVENT WRITE IMPOSSIBLE ,UNLIKELY , EQUALLY LIKELY , LIKLEY OR CERAIN

Answers

Answer: LIKLEY

Step-by-step explanation:

Formula : Probability [tex]=\dfrac{\text{Number of favorable outcomes}}{\text{Total outcomes}}[/tex]

A standard cube has six numbers on it (1,2,3,4,5 and 6).

P( NOT 6) =[tex]\dfrac{\text{Numbers that are not 6}}{\text{Total numbers}}[/tex]

[tex]=\dfrac{5}{6}=0.8333[/tex]

We know that when the probability of any event lies between 0.5 and 1then the event is said to be likely to happen.

Since , P(not 6)=0.8333 which lies between 0 and 0.5.

That means, it is likely to happen.

Note :

When probability of having A = 0 , we call A as uncertain event.

When probability of having A = 1 , we call A as certain event.

When probability of having A = 0.5 , we call A as equally likely event.

When probability of having A lies between 0 and 0.5 , we call A as unlikely event.

When probability of having A lies between 0.5 and 1 , we call A as likely event.

On hot, sunny, summer days, Jane rents inner tubes by the river that runs through her town. Based on her past experience, she has assigned the following probability distribution to the number of tubes she will rent on a randomly selected day.

x 25 50 75 100 Total
P(x) 0.16 0.36 0.38 0.10 1.00

Find the probability expressions: (Round your answers to 2 decimal places.)

a. P(X=50)P(X=50).
b. P(X≤75)P(X≤75).
c. P(X>50)P(X>50).
d. P(X<100)P(X<100).

Answers

Answer:

a. P(X=50)= 0.36

b. P(X≤75) =  0.9

c. P(X>50)=  0.48

d. P(X<100) = 0.9

Step-by-step explanation:

The given data is

x                      25        50       75        100          Total

P(x)                0.16       0.36    0.38    0.10          1.00

Where X is the variable and P(X) = probabililty of that variable.

From the above

a. P(X=50)= 0.36

We add the probabilities of the variable below and equal to 75

b. P(X≤75) = 0.16+ 0.36+ 0.38= 0.9

We find the probability of the variable greater than 50 and add it.

c. P(X>50)= 0.38+0.10=  0.48

It can be calculated in two ways. One is to subtract the probability of 100 from total probability of 1. And the other is to add the probabilities of all the variables less than 100 . Both would give the same answer.

d. P(X<100)= 1- P(X=100)= 1-0.1= 0.9

A
B
C
D
Help me out

Answers

Answer:

2x^2 + 3/2x -5

Step-by-step explanation:

f(x) = x/2 -2

g(x) = 2x^2 +x -3

f(x)+ g(x) =  x/2 -2+ 2x^2 +x -3

Combine like terms

             = 2x^2 + 3/2x -5

After the accounts have been adjusted at December 31, the end of the fiscal year, the following balances were taken from the ledger of Pioneer Delivery Services Co.:
Kerry Buckner, Capital. $9,556,300
Kerry Buckner, Drawing 80,000
Wages Expense 1,878,400
Rent Expense 1,415,500
Supplies Expense 125,000
Fees Earned 30,600
Miscellaneous Expense 22,100
Journalize the two entries required to close the accounts.

Answers

Jhdbdhdhrkhbe’h546;&7;;$4

A rectangular field has an area of 1,764 m(squared). The width of the field is 13 m more than the length. What is the perimeter of the field?

Answers

Answer:

170m

Step-by-step explanation:

The answer to the above question is letter d which is 170 m. To get the 170 m, kindly check the below solution: 

x^2 + 13x = 1764 so x = -49 and 36, we take 36 as its the positive value. And the other side is 49. Now use 2(l+b) to find perimeter. You get (36+49)*2 = 170

Please help. I’ll mark you as brainliest if correct!

Answers

Answer:

product = 40

Step-by-step explanation:

The conjugate of (-2 + 6i) is (-2 - 6i)

You just need to change the sign

(-2 + 6i) (-2 - 6i)

Expand:

4 + 12i + -12i - [tex]36i^{2}[/tex]

4 + 12i + -12i + 36

product = 40

A team of researchers published an article on the study of how vehicles are dispatched based on an airport-based taxi service. The researchers modeled this system with an underlying assumption that travel times of successive trips to and from the terminal are independent exponentially distributed random variables with β = 15 minutes. (a) Find the mean and standard deviation of trip time distribution (b) How likely is it for a particular trip to take more than 25 minutes? (c) If two taxis are dispatched together, what is the probability that both of them will be gone for more than 25 minutes? (d) what is the likelihood of at least of one of the taxis returning within 25?

Answers

Answer:

a. The mean would be 0.067

The standard deviation would be 0.285

b. Would be of 1-e∧-375

c. The probability that both of them will be gone for more than 25 minutes is 1-e∧-187.5

d. The likelihood of at least of one of the taxis returning within 25 is 1-e∧-375

Step-by-step explanation:

a. According to the given data the mean and the standard deviation would be as follows:

mean=1/β=1/15=0.0666=0.067

standard deviation=√1/15=√0.067=0.285

b. To calculate How likely is it for a particular trip to take more than 25 minutes we would calculate the following:

p(x>25)=1-p(x≤25)

since f(x)=p(x≤x)=1-e∧-βx

p(x>25)=1-p(x≤25)=1-e∧-15x25=1-e∧-375

c. p(x>25/2)=1-p(x≤25/2)=1-e∧-15x25/2=1-e∧-187.5

d. p(x≥25)=1-e∧-15x25=1-e∧-375

Find f(g(−1)), f(g(−1))=___

Answers

Answer:

Find g(f(−1)).

g(f(−1)) =  64

Find f(g(−1)).

f(g(−1)) = -6

f(g(−1)) is - 8.

What is a composite function ?

A composite functions is a function where two or more than two functions are combined.The output of the previous function is the input of the next function.

According to the given question we have to find a composite function.

Assuming f(x) = x² + 9x and g(x) = .

To find f(g(-1)) first we have to put x = -1 for g(x) which is

= g(-1) = (-1)³ = -1.

Now we put this value of g(-1) in f(x).

∴ f(g(-1))

= f(-1)

= (-1)² + 9(-1)

= 1 - 9

= - 8.

learn more about composite functions here :

https://brainly.com/question/20379727

#SPJ2

Complete the synthetic division problem below.
2 1 6 -16
What is the quotient in polynomial form?

Answers

Answer: x + 8

Step-by-step explanation:

The required quotient in polynomial form is x + 8.


To determine the synthetic division of 2 | 1 6 -16 and quotient in polynomial function.


What is synthetic division?

It is a method for performing division of polynomials, with little writing and lesser calculations than complex division.

2   |    1      6      -16
               +2     +16        
         1      8       0  
Its quotient in polynomial form is given as x + 8


Thus, The required quotient in polynomial form is x + 8.

Learn more about synthetic divisions here:
https://brainly.com/question/11850611
#SPJ5

A typical classroom is a rectangle with dimensions of 20 feet wide by 25 feet long, and the area needed for each person in the room is approximately 28 square feet, what fraction of the total area in a classroom is needed for each person? What is the largest number of people that would fit in an average sized classroom while practicing good social distancing?

Answers

Answer:

A fraction of 0.056 of the classroom is needed for each student.

A typical classroom can acomodate up to 17 persons while practicing good social distancing.

Step-by-step explanation:

We have a classroom that is a recatngle with dimensions of 20 feet wide by 25 feet long.

The total area of the classroom is:

[tex]A=w\cdot l=20\cdot25=500[/tex]

As the area of the classromm is 500 square feet and we need 28 square feet for each student, the fraction that is needed for each student is:

[tex]f=\dfrac{A_{\text{student}}}{A_{\text{classroom}}}=\dfrac{28}{500}=0.056[/tex]

A fraction of 0.056 of the classroom is needed for each student.

The largest number of students that would fit in an average sized classroom while practicing good social distancing can be calculated dividing the area of the classroom by the area needed for each student. This is equal to the inverse of the fraction calculated previously:

[tex]n=\dfrac{1}{f}=\dfrac{1}{0.056}\approx17.86[/tex]

A typical classroom can acomodate up to 17 persons while practicing good social distancing.

Design and complete a frequency table for Belinda.
Belinda ask 20 people, how many hours of TV did you watch last week?

Here is the results
3,17,4,4,6,11,14,14,1,20,9,8,9,6,12,7,8,13,13,9.
Belinda wants to show these result in a frequency table.
She will use 4 equal groups.
The first group will start with 1 hour and the last group will end with 20 hours.

Answers

Answer:

Step-by-step explanation:

Since she will use 4 groups or class intervals, the the class width would be 20/4 = 5 hours

The class groups would be

1 to 5

5 to 10

10 to 15

15 to 20

The class mark for each class is the average of the minimum and maximum value of each class. Therefore, the class marks are

(1 + 5)/2 = 3

(5 + 10)/2 = 7.5

(10 + 15)/2 = 12.5

(15 + 20)/2 = 17.5

The frequency table would be

Class group Frequency

1 - 5 4

5 - 10 8

10 - 15 6

15 - 20 2

The total frequency is 4 + 8 + 6 + 2 = 20

Help asap giving branlist!!!

Answers

Answer:

Option 2

Step-by-step explanation:

Because the slope is -0.09 the answer is the second option. A negative slope means a decrease.

The Bureau of Transportation Statistics Omnibus Household Survey is conducted annually and serves as an information source for the U.S. Department of Transportation. In one part of the survey the person being interviewed was asked to respond to the following statement: "Drivers of motor vehicles should be allowed to talk on a hand-held cell phone while driving." Possible responses were strongly agree, some what agree, some what disagree, and strongly disagree. Forty-four respondents said that they strongly agree with this statement, said that they some what agree, said they some what disagree, and said they strongly disagree with this statement.

Required:
a. Do the responses for this statement provide categorical or quantitative data?
b. Would it make more sense to use averages or percentages as a summary of the responses for this statement?
c. What percentage of respondents strongly agree with allowing drivers of motor vehicles to talk on a hand-held cell phone while driving?
d. Do the results indicate general support for or against allowing drivers of motor vehicles to talk on a hand-held cell phone while driving?

Answers

Step-by-step explanation:

a. It would provide a quantitative data

b. Yes, it would make more sense to use percentages rather than averages as this is estimating a proportion.

c. 44% of the respondents strongly agree

d. the results do not indicate general support for or against allowing drivers of motor vehicles to talk on a hand-held cell phone while driving as the only respondents will be those that agree with the researchers claim and the study will be biased against those who do not agree.

write any two numbers less than 15 , which has exactly four factors​

Answers

Answer:

4 can be divided by 1 and 2

6 can be divided by 1 and 2

12 is wrong because it can be divided by 1,2, and 4 so it has 6 factors instead of 4

Step-by-step explanation:

Tacoma's population in 2000 was about 200 thousand, and has been growing by about 8% each year. If this continues, what will Tacoma's population be in 2013?

Answers

Answer: The population will be 408,000 people.

Step-by-step explanation:

So in 2000 there were 200,000 people and it started to grow 8% every year so up to 2013.

so find 8% of 200,000 and then multiply it by the  the number of years.

8% * 200,000 =  16,000

Find the difference between the years.

2013 - 2000 = 13 years

13 * 16000 = 208000  This is the amount of new people from 2000 to 2013 so add it to the original population.

208,000 + 200,000 = 408,000  

Solve:

|x-7|<-1.

zero solutions
one solution
infinite solutions
all real numbers

Answers

Step-by-step explanation:

In mathematics, the absolute value |x|, is the non-negative result of x without regard to its sign.

An absolute function, can never have a negative result.

By this alone, you can solve the question because the inequality is false, and therefore there are zero solutions.

Please see the attachment of f(x) = |x - 7|.

When you look at the graph, you can easily confirm that there is no value which can result in a negative y- coordinate like -2. In fact, that is the whole purpose of any absolute value or function. The result of an absolute function can never be negative.

Please answer this correctly

Answers

Answer:

Set the height up to 4

Step-by-step explanation:

Since there are 4 numbers between 1-5, set the height up to 4

Answer:

4 temperature recordings.

Step-by-step explanation:

2, 2, 4, 5

There are 4 recordings in the range of 1-5°C.

A high school student took two college entrance exams, scoring 1070 on the SAT and 25 on the ACT. Suppose that SAT scores have a mean of 950 and a standard deviation of 155 while the ACT scores have a mean of 22 and a standard deviation of 4. Assuming the performance on both tests follows a normal distribution, determine which test the student did better on.

Answers

Answer:

Due to the higher z-score, he did better on the SAT.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Determine which test the student did better on.

He did better on whichever test he had the higher z-score.

SAT:

Scored 1070, so [tex]X = 1070[/tex]

SAT scores have a mean of 950 and a standard deviation of 155. This means that [tex]\mu = 950, \sigma = 155[/tex].

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{1070 - 950}{155}[/tex]

[tex]Z = 0.77[/tex]

ACT:

Scored 25, so [tex]X = 25[/tex]

ACT scores have a mean of 22 and a standard deviation of 4. This means that [tex]\mu = 22, \sigma = 4[/tex]

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{25 - 22}{4}[/tex]

[tex]Z = 0.75[/tex]

Due to the higher z-score, he did better on the SAT.

Other Questions
The price of a visit to the dentist is $50. If the dentist fills any cavities, an additional charge of $100 per cavitygets added to the bill. 10)What does mRNA copy and carry the code to produce? (1pt)a)DNA b)Proteins (URGENT)use the vectors to determine two dot products A school needs 1,860 pencils for its students. The pencils are sold in boxes of 12. How many boxes does the school need to order? Fully Factorise 5k^2+7k Which is the best estimated pressure, represented in units of GPa, of the lower mantle? 110 GPa 220 GPa 305 GPa 360 GPa verify clairaut's theorem for u=e^xysiny I will Rate you 5 stars and give you 30 pointsA rectangle is graphed on the coordinate grid. Which represents the equation of the side that is parallel to side s? y=-x+9 y=-x-3 y=x+9 y=x-3 which statements correctly describe the association between the variables A and B ? select each correct answer. I need help ASAP I shall give brainlyist (idk how to spell) Madeline is writing a computer program for class. The first day she wrote 5 lines of code. She wrote 15 lines of code on the second day and 45 on the third day. Find the total amount of lines of code written after all 6 days. 2 PointsThe Supreme Court serves what important function in the U.S. federalgovernment?A. It determines whether cases should be reviewed in the federal orstate judiciary systems.O B. It promotes the principle of limited government by consistentlypracticing judicial activism.O C. It establishes legal precedents that are almost always followed bylower courts.D. It exercises a check on congressional power by legally lifting filibusters when necessary.The answer is C. It establishes legal precedents that are almost always followed by lower courts. What do you predict would happen if you placed the smaller ball on the bottom, and thelarge ball on top? Be sure to support your claim with evidence. what is one of the cause of mechanical weathering A. acid rain B. Oxidation C.animal actionsD. Carbon Find the slope-intercept equation of the line containing (1.-4) and having slope m = 3 The payback period provides information to managers that can be used to help a.control the risks associated with the uncertainty of future cash flows. b.minimize the impact of an investment on a firm's liquidity problems. c.control the effect of the investment on performance measures. d.control the risk of obsolescence. e.All of these choices are correct. 1. What is the main idea in High Incomes Don't Bring You Happiness"|| Can someone please help me with this question please:( HELLO ! HELP ME PLEASE.I am French and my English teacher asked me to connect with a relative pronoun. Are enzymes in saliva a example of a structural adaption or physiological?