Answer:
The correct answer is - А. experiment.
Explanation:
An experiment is a type of research method used for scientific investigation to check how a natural phenomenon works and how a particular variable affected by causing or manipulating one variable.
The affected variable called the dependent variable and the variable that is changed is called the independent variable. Other than independent variables other variables should be controlled so there would be no influence on the result other than independent varibles.
I don't know how specific you need to get for this question. The basic answer would be the mitochondria as it is where the Krebs Cycle, the Electron Transport Chain, and Chemiosmosis (also referred to as oxidative phosphorylation) all occur. Chemiosmosis is where the majority of ATP is produced during cellular respiration, and it primarily occurs in the matrix of the mitochondria as protons move down the gradient through ATP Synthetase channels.
Answer: adenine, thymine, guanine and cytosine
Explanation: Adenine always binds with thymine, and cytosine always binds with guanine.