Answer:
2 membrane layers cover up the nucleus
The scientist will add up the mass of the protons and mass
of the neutrons to come up with the approximate mass of atom because protons
and neutrons is what consist of the atoms. Therefore, in order to have the approximate
mass of an atom, adding the mass of protons and neutrons will give the result.
Answer: It means to guide and regulate chemical and physical parameters to keep your body or environment in a constate state for proper functioning.
Explanation: This is called homeostasis. The body has systems in place to monitor its components such as cells, organs and any other molecule needed to maintain life and good health. The body needs to maintain its temperature at 37°C, pH of blood at 7.4, water balance, osmotic pressure, growth rate and tissue repairs whenever it dictates the need, danger of infection or injury.
All of these form an integral part of a healthy living organism and it needs to always be stable, regulated and monitored. This is called maintaining homeostasis.