Answer:
An organ system is a group of organs that work together to perform a complex function. There are eleven organ systems in the human body. All of these are required for survival, either of the person or of the species.
Explanation:
Biotic means living (can reproduce, has dna, can go through homeostasis) abootic mean non living (like a desk, table, chair, etc.)
First one - two gametes will unite during fertilization to create a diploid cell
It is the manipulated variable. It is changed in an experiment to see how it would effect another variable.