A) Vibrations
Sounds vibrate the eardrum
Vein because they have valves to prevent back flow of blood.
It is becuase those people came from different places and mated with others leading to a combination of dirrerent traits.
Answer:
Everything in Earth's system such as water, land, air, and or living things.
Explanation:
All those things are called "Spheres" or specifically =
1- Hydrosphere (water)
2- Lithosphere (land)
3- Biosphere (living things)
4- atmosphere (air)
