The answer is genetic drift.
Water
Soil
The sun
Atmospheric Gases
Temperature.
These are just a few of many, but all abiotic factors are not living. Hence A-Biotic
Biotic means living, so when you put the ''a'' prefix it means the opposite of living.
Answer:
A dolphin's flipper, a bird's wing, a cat's leg, and a human arm are considered homologous structures. ... Bats, whales, and many other animals have very similar homologous structures, demonstrating that these creatures all had a common ancestor
Just don't worry about the human part
hope this helps