18: D, homologous
20: B, DNA
I can’t see 17 or 19!
The Richter scale is a way of giving the intensity of all earthquakes a numerical value. this allows the strengths of different earthquakes to be compared. Because of this, i think the best answer is D
Answer:
it affects the hardness of the shells because calcium has a high reactivity which causes the shell to be hard
Explanation:
B.) Glucose because in order for that person to have energy that person has to have sugar to be active...