You are given a science question (hard-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: In mice, a certain species displays incomplete dominance in coat coloring. The offspring of a black (BB) mouse and a white (bb) mouse are gray (Bb) mice. A cross between two gray mice will most likely produce offspring with which percent of coat colors?  
 (A) 25% black, 75% gray (B) 25% gray, 75% white (C) 25% white, 25% black, 50% gray (D) 25% gray, 25% black, 50% white

A: C
****
Q: Two layers of sedimentary rock are exposed on the side of a hill. Only one of the layers has fossils. The lack of fossils in one layer of sedimentary rock is most likely due to  
 (A) changing environments. (B) volcanic activity. (C) changing rates of erosion. (D) evaporation of sea water.

A: A
****
Q: Nick is making a model to show how human skin covers the body. What material would work best?  
 (A) a sheet of rubber (B) a sheet of paper (C) a sheet of metal (D) a sheet of wood

A:
A
****