Answer:
Ne-21
Explanation:
the 21 represents the mass number. since neon has 10 protons, the mass number is calculated by adding the number of neutrons to 10.
this is because mass number = protons + electrons
so 10 +11 =21
Answer:
I think it's the 3rd one....anything with molecules; matter
Cells are what make up organisms. Cells make tissues, tissues make organs, organs make systems, and organ systems make organisms.
<span>maintains a constant INTERNAL environment
so other options included internal variable and external environment. but its internal and environment</span>
Answer: C
Explanation: Earth's atmosphere isn't very dense because it is made of air, which floats. Human beings are denser then air since they are solid, but not as dense as Earth's crust, which is rocky and the densest out of the three.
