1.
The basic building unit of bone
2.
The muscle in the heart/involuntary
3.
Top left chamber of the heart
4.
The main artery in the body
5.
The process in which water turns into vapor
6.
What returns nitrogen back to the soil
8.
all members of the same species in an area at the same time
9.
Anything that restricts the size of a population
11.
helps you bend your arm
12.
helps you straighten your arm
13.
pulls your arms across your body
