Which of the following factors do you think can affect the size and structure of a population? the number of individuals who enter a population
the number of individuals who exit a population
limitation of resources
natural events
human activity
DONE
Intro

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.

i believe your answer would be c.. : )