Answer:
The animal gets energy from the food
Answer:
The growth of the plants is the dependent variable, the stuff added to each plant is the independent variable, the plants that don't receive treatment/other stuff are control variables.
It happens when the two groups become sufficiently different and the two can no longer interbreed. A known example of speciation is the London underground mosquito where it formed a new species within the existing genus. There are examples in micro-evolution but not in macro-evolution.
