Which reproduction uses non reproductive parts of a plant to reduce new plains ​

Can you guys me with this question , and you! : why do you think the breastbone of a bird is so much larger than the breastbone of a cat?

Ineed to know why d is the correct answer asap

Need an answer asap 45 points and brainlest to the first person to answer why do scientific theories, such as biological and chemical evolution, represent the strongest explanation of the changes observed in the fossil record. must be in sentence form how can scientific theories on evolution and the fossil record change over time? must be in sentence form