Answer: A substance is matter which has a specific composition and specific properties. Every pure element is a substance. Every pure compound is a substance. Examples of substances: Iron is an element and hence is also a substance.
Explanation:
Answer:
The nervous system helps all the parts of the body to communicate with each other. It also reacts to changes both outside and inside the body. The nervous system uses both electrical and chemical means to send and receive messages.
Explanation:
I would say D because both populations are constantly growing and it would be natural selection so it works out if humans just back off
Answer:
C. Hypothesis
Explanation:
Hypothesis is a proposed explanation for a certain occurrence and when the explanation is conclusive, then it becomes a theory.
Through a series of tests and data
