Which of the following is usually most helpful in determining the age of these fossils? A. The size of the fossils
B. The color of the fossils
C. The amount of surface area of the rock layer in which the fossils are found
D. The depth of the rock layer in which the fossils are found

D. The depth of the rock layer in which the fossils are found

Explanation:

Size is irrelevant because a t-rex and ancient hamsters lived together

Color is irrelevant, because with time, almost all fossils are a grey tone look

D.) is the better answer between C.) & D.) because layers of the earth are used in the approximation of the time period in which the dinosaur lived