C and D are the right answer. I hope this helps (please give me brainliest)
Answer:
Mutualism: It is a type of symbiotic relationship between two organisms in which both the organisms gets benefits to each other.
For example, in leguminous plants a bacteria is present in the roots of the plants and make symbiotic relationships with each other. In this relationship, plant provides habitat and food to the bacteria and in return the bacteria fixes atmospheric nitrogen for the plant and both get benefit.
both immigration and births add individuals to a population.