1) Variation: there needs to be a difference in the individuals within a population
2) Inheritance: These variable traits must be able to be passed down genetically
3) Growth rate: There needs to be a growth rate that requires a struggle for resources
4) Survival rate: There needs to be a difference in survival rate for the different variation types... certain variations will live
Answer:
Animal Respiration Every cell in an animal requires oxygen to perform cellular respiration. Cellular respiration is the process by which animals take in oxygen and exchange it for carbon dioxide and water as waste products.
Answer:
I have a chart for this if you'd like that it really helps to better understand the Nitrogen Cycle and how it works.
