What is the only thing that should differ between experimental treatments

How does the study of genetic disorders such as pku biologists understand normal alleles?

Which of the following types of reactions would decrease the entropy within a cell? a. dehydration reaction, b. hydrolysis, c. respiration, d. digestion, e. catabolism.

Kudzu vines grow by climbing and wrapping around trees. trees covered by kudzu can die because they are starved of sunlight. what type of relationship exists between the trees and the kudzu growing on them?