Conservationists occasionally light forests on fire to control wild fires. By occasionally burning material (like leaves, branches, etc), those materials cannot build up and cause large and uncontrollable fires later.
The cell copies its DNA during DNA replication.
B: Antigens
Explanation: Antigens itself are the invaders that causes an infection or a disease in living organism. They do not protect against invaders in non-specific response as they themselves are the ones who are invading the body.
Digestive enzymes are the enzymes that act on a particular substrate for its action at a particular PH.
Stomach acid is the hydrochloric acid that keeps the PH of the stomach low and prevents the growth of unwanted pathogens.
Lysosomes have digestive enzymes in it. It performs the process of phagocytosis.
I think the correct answer would be strong gravity. The factor that allows the earth to hold onto water would be the strong gravitational pull of the earth. In fact, it is what holds everything onto earth not only water. Hope this answers the question.
