What are Some of the characteristics that vertebrates share( choose all that apply) 1. Highly developed senses and nervous systems
2. Endoskeletons and a backbone
3. External protective structures
4. Joint appendages

This answer Is Endoskeletons and a backbone

1,2, and 4

Explanation:

ok

explanation:

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.