You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

[Q]: The incompleteness of the fossil record results primarily from which phenomenon?
(A) the frequency and irregular timing of organism speciations (B) the metamorphosis of most sedimentary rock by heat and pressure (C) the geologically rapid cycling of crust material back into the mantle (D) the rarity with which organic remains are exposed to fossil-forming conditions
[A]: D

[Q]: What is the main function of red blood cells?
(A) To fight disease in the body (B) To carry oxygen to all parts of the body (C) To remove carbon monoxide from all parts of the body (D) To produce materials which cause the blood to clot.
[A]: B

[Q]: How do plants get water and minerals?
(A) absorbed from the soil though the roots (B) absorbed from the soil through the stem (C) absorbed from the air through the flowers (D) absorbed from the air through the leaves
[A]:
A