20. The answer is 1 (Precambrian)
21. The answer is 4 (Pennsylvanian)
22. The answer is 2 (Bony Fishes, Dinosaurs, and Mammals)
23. The answer is 2 (Reptiles)
Answer:
in my opinion I think it's amino Acids
Answer:
Increased fitness of large-beaked birds, leading to natural selection
(Why: Birds with larger beaks are better able to survive in the new enviornment)
Hope this help
Have a wonderful day!!
