The correct answer is biological anthropology, or physical anthropology.
It is centered around human beings only, with respect to their common or different features that they either share or don't share with their related non-human primates and other ancestors. It deals with human evolution, the study of their behavior, reproduction, etc.
The independent variable in the hypothesis of an observed increased in sea turtle sickness once an increase in red tide can be seen would be the increase of red tide.
The reason for this is that red tide increases or decreases will happen independently of the amount of sea turtle sickness - therefore increasing sea turtle sickness will be dependent on the first variable. (independent one).
The term is called a theory.
In scientific investigation, a theory is a well substantiated explanation of how a particular phenomenon works based on the set of facts which had been repeatedly confirmed through observations and experiments. A scientific theory gives reliable account of a phenomenon.
<span>Elements are combined, they form a Compound. When a group of atoms are combined, they create a molecule. </span>