Answer:A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled. The independent variable is the one that is changed by the scientist.
Explanation:
Answer:
Predict what might happen if there were no nitrogen-fixing bacteria on Earth?
The earth would stink if there are no nitrogen-fixing bacteria as they are decomposer
Explanation:
Embryo, Sac, Zygote, Embryo