A student is investigating which type of soil is best for growing tomato plants from seeds. The student plants four tomato seeds in each of three different containers of soil. Which step of the procedure would help the student get the most reliable results?
A: Change only the soil type in each container.

A student pours a clear liquid from a test tube into a beaker with a clear liquid already in it and notices that the mixture turns pink. The student infers the two clear liquids are different. This inference is a result of
A: student observations.

If its food supply in a field decreases, the mouse population in that field will probably
A: decrease.

In the life cycle of a fly, which stage comes after the larval stage?
A:
pupa