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.

Sickle cell anemia is a genetic disease caused by an autosomal recessive gene. If each parent carries one sickle cell allele, what are the chances that their child will have sickle cell anemia?  
 (A) no chance (B) one in four (C) two in four (D) three in four
B

Which organisms contribute most to the decomposition of dead organisms?  
 (A) snakes (B) viruses (C) insects (D) bacteria
D

The position of the liver in the circulatory system maximizes its ability to filter out harmful chemicals as soon as they enter the bloodstream. Blood travels to the liver from the  
 (A) nervous system. (B) digestive system. (C) immune system. (D) excretory system.

B