Answer:
The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
It determines how the population is decreasing and increasing.
The pressure from sound waves makes the eardrum vibrate.
The vibrations are transmitted further into the ear via three bones in the middle ear : the hammer (malleus), the anvil (incus) and the stirrup (stapes).
In a food chain, plants are primary producers, as they produce biomass.
Answer: plants