The <u><em>correct answer</em></u> is:
He needs to select a more representative sample.
Explanation:
Choosing students from the basketball team for the sample he uses on a study of heart rates and exercise will be a biased sample. This is because students on the basketball team are potentially healthier than other students, which means that exercise will not have a large an effect on their heart rate as it would if they were not as healthy and not as physically fit.
In order to reduce the amount of bias, he should choose students from different groups throughout the school.
Humans disturb the earth and because of this, the earth is weakened.
idgis primarily found on the surface of B lymphocytes where it functions as a receptor for antigen.
img antibodies are found in blood and lymph fluid and are the first type of antibody made in response to an infection. They also cause other immune system cells to destroy foreign substances.
Answer:
The nervous system is the part of an animal's body that coordinates its behavior and transmits signals between different body areas.