20 is the Number of Neutrons of potassium.
Answer: Option C.
The number of protons and neurons it's contain.
Explanation:
Mass number of an atom is also called atomic mass of an atom which is some what expressed in Dalton i.e 1/2. The mass number is the total number of protons and neutrons altogether called nucleons in an atomic nucleus.
Example of multi cropping is tomatoes+onions+marigold
Answer:
A closed system is a physical system that does not allow transfer of matter in or out of the system, though, in different contexts, such as physics, chemistry or engineering, the transfer of energy is or is not allowed.
Answer:
Explanation:
Do nguyên phân làm tế bào con giống với tế bào mẹ ban đầu