Adevice used to clean exhaust gasses before they exit the cars tailpipe is called?

What came first the elephent or the crocodile

In this experiment, the was intentionally manipulated. it is the independent variable. the dependent variables that were measured were the

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