The observation that the front limbs of birds and reptiles have similar homologous structures supports which of the following?

birds and reptiles use these structures for the same motion.

birds and reptiles developed in parallel without relation.

birds and reptiles evolved from a common ancestor.

birds and reptiles were influenced by the same environmental factors.

The correct answer would be "Birds and reptiles evolved from a common ancestor".

Homologous organs or structures refer to the set of organs or structure which are similar in internal structure but vary in their functions. The similar structure often demonstrates the common origin or ancestors.  

Different organisms adapt to perform different functions as an adaptation against the varying environment.

For example, front limbs of reptiles and birds are similar in structure as they are made up of a similar set of bones, however, they differ in their functions due to adaptations against the varying environment.

The correct answer would be "Birds and reptiles evolved from a common ancestor".

Explanation:

i'd say that the moon rock is about 2.2 billion years old.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.