The climate and features of the Earth are always changing. Some populations have been able to survive by adapting to the changes. Which characteristic of a population is most vital for allowing adaptation?
A. genetic variation
B. population size
C. immunity to disease
D. energy requirements

Astudent wants to test the hypothesis that fertilizer improves the growth rate of grass seeds. to test this hypothesis, the student put the same amount of grass seed in 3 containers with the same type of soil. the student measured the growth at the end of the week. all plants received equal amounts of water and sunlight. if you were asked to graph this data, what would you place on the x-axis? a. fertilizer b. water c. plant growth d. week one

In the presence of oxygen, glycolysis is followed a. the krebs cycle b. lactic acid fermentation c. alcoholic fermentation d. photosynthesis

Which structure in the cardiovascular system connect arteries to veins?