What is the question here? There’s multiple answers
Answer:
Diffusion rate is 1.96 × 
/s
Explanation:
Diffusion is the process in which the molecules of a substance propagates from a region of higher concentration to region of lower concentration through a semi-permeable membrane.
diffusion rate = 
Given that; diameter = 15 mm, time = 15 minutes.
The dye spread in a circular form, so that;
area = 
r = 
= 
= 7.5 mm = 0.75 cm
area = 
× 
= 1.7679
time = 15 minutes = 15 × 60 = 900 seconds
So that;
diffusion rate = 
= 0.0019643 /s
Diffusion rate is 1.96 × /s
In some types of research the target population might be as broad as all humans, but in other types of research the target population might be a smaller group such as teenagers, pre-school children or people who misuse drugs.
It is more or less impossible to study every single person in a target population so psychologists select a sample or sub-group of the population that is likely to be representative of the target population we are interested in.
This is important because we want to generalize from the sample to target population. The more representative the sample, the more confident the researcher can be that the results can be generalized to the target population.
One of the problems that can occur when selecting a sample from a target population is sampling bias. Sampling bias refers to situations where the sample does not reflect the characteristics of the target population.
Origin of species by means of natural selection
Instructions for making proteins are stored in DNA
