Overhunting of large mammals.
Answer:
1. The descendants are Blue whales, and Humans
2. Back bone Lungs , radius and ulna (front limb bones), structures for producing milk
Explanation: It points to the descendants of common ancestors to blue whales and humans, If not please tell me more clearly what you meant by descendants.
Producers are normally plants and the consumers are therefore herbivores
The answer is c or a its one of the two