Cancer is uncontrolled cell division.
Answer:
C
Explanation:
Membranes will allow and inhibit certain ions/molecules. I don't believe it can distinguish whether the molecules are harmful or beneficial!
Though they are constantly changing, ecosystem are naturally BALANCED.
An ecosystem is said to be balanced, when the components of the ecosystem are in harmony. Two of the principal processes that usually throw ecosystems out of balance is pollution and hunting.
