If you are implying one these choices not needed for survival it would be parents only when you can survive on your own (I'm not that sure but I hope this helped the slightest but)
Answer:
24 million years
Explanation:
A: GCACTAAGCATCGATTT
B: GCACCAGGCACTGGTTC
There are 6 base pair changes between species A and species B. Since we know the rate of change is 1 base pair every 4 million years, we know 6x 4 million is likely how long ago the species diverged. 6x 4 million = 24 million years
Answer: (c) skeleton
Explanation: The musculoskeletal system is made up of the body's bones (the skeleton), muscles, cartilage, tendons, ligaments, joints, and other connective tissue that supports and binds tissues and organs together.
D. pressure from lava being pushed up from th earth adds new material to the ocean floor, creating a ridge