In an experiment to test the hypothesis that added phosphate will cause marigolds to produce more blooms, the experimenter has two groups of pots planted with marigold seeds. one group gets watered with phosphate added to the water, while the other 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. number of pots
b. amount of water
c. amount of phosphate
d. amount of blooms on a plant

Which of the following is the most likely result of converting forestland to urban development? a. the amount of land available for lumber production decreases. b. fewer trees are needed because cities are made mainly of concrete. c. people discover more efficient ways to grow trees. d. the price of lumber goes down.

During the process of two rails or sides break apart and attract new nucleotide bases to form a new and complete strand.

This is a typical grassland food web. it is also a small picture of an important cycle on earth: the carbon cycle. describe how the carbon gets into this food web. a) bacteria and fungi, the decomposers, recycle carbon from dead organisms. b) carbon is found in the grass and is passed from one level to the next in this food web. eliminate c) all living things give off carbon dioxide as a by-product of respiration and it is released into the atmosphere. d) plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.