Which factor best explains why classification systems change over time?
a. changing environments lead to reclassification
b. increased plant species leads to reclassification
c. changes in food sources leads to reclassification
d. increased knowledge of genetics leads to reclassification

The correct answer is option D. increased knowledge of genetics leads to reclassification.

Explanation:

The classification system was initially was made on the basis of the similarities in their physical, internal characters and their habitats. Classification systems are always subject to update, based on the different factors.

The increased knowledge of the genome and the DNA is helping to tell that the species or organisms look different in several ways are actually closely related or share the ancestry.

Thus, the correct answer is option D.

the answer is d p: cell, q: organ, r: organ system, s: tissue