Which line of defense includes active immunity? 1. first
2. Second
3. third
4. fourth

What are four key elements of the study of economics?

Liquid water turns into water vapor at which step in the water cycle

Need an answer asap 45 points and brainlest to the first person to answer why do scientific theories, such as biological and chemical evolution, represent the strongest explanation of the changes observed in the fossil record. must be in sentence form how can scientific theories on evolution and the fossil record change over time? must be in sentence form