Asap! 20 points! in an experiment to test the hypothesis that added phosphate will cause marigolds to produce more blooms, the experiments has two groups of pots planted with marigold seeds. one group gets watered with no phosphate. both groups get the same amount of water and light. which is a controlled variable in this experiment? a) numbers of pots b) amount of water c) amount of phosphate d) amount of blooms on a plant

Vegetation that grows along the floors of tropical and temperate forests is called undergrowth. how is the undergrowth of a tropical rain forest most likely to differ from the undergrowth of a temperate forest? a. a tropical rain forest's undergrowth most likely experiences periods of dormancy during colder weather. b. a tropical rain forest's undergrowth most likely experiences periods of dormancy during rainy weather. c. the undergrowth of a tropical rain forest most likely requires less sunlight. d. the undergrowth of a tropical rain forest most likely requires more sunlight.

The distribution of related animals and plants across the world

Why are scientists concerned about the depletion of the ozone levels in the stratosphere?