Answer:
over time, one natural area is replaced by another.
Step-by-step explanation:
these are not seasonal changes, and time is clearly passing in the images, and fish are not relevant to the question.
I believe the answer is one.
The answer is nearly 124 cm square
Answer: 20
Step-by-step explanation:
Formula to find the sample size : 
Given : Significance level : 
Critical value : 
Margin of error : 
Standard deviation: 
Then, we have

Hence, the minimum sample size must be 20.