The________________variable is the variable that is manipulated by the researcher in the experiment. 

The pituitary gland is often called the “master gland” because it influences the other endocrine glands.

Correlation is not the same as causation.

Root hairs

Americans historically have been interested in two aspects of plant use

Early American farmers faced a surplus problem because

The term used to describe united sepals is

Plants that drop their leaves and appear dead but are actually alive are:

Which of the following best describes a motor unit?

A plant stores food in the form of starch, has cell walls, and contains chlorophyll a and b.