Answer: Natural selection is one of the forces of evolution and the enviroment where the species lives is the selection agent. For example, suppose a mosquitoes population in a environment free from insecticides, in this environment there's a high frequency of non-resistant mosquitoes because the environment is not exerting any pressure on the resistence trait. But when the environment changes and we use a insecticide upon the mosquitoes population, the populations changes because the non-resistant ones die but those resistant survive and beggin to reproduce more effectively. That's natural selection, differences in survival and reproduction between individuals with different phenotypes (traits) and this differences depend of environmental changes.
I think about 60 g/m^2 is released into the atmosphere as a result of the metabolic activity of herbivores. Metabolism is the sum of the chemical reactions that take place within a cell of a living organisms and that provide energy energy for vital processes and also for synthesizing new organic material. In herbivores, cellular respiration is the major process that releases carbon dioxide in the atmosphere.
Mountain chains match up where South America collided with Australia to form Pangaea.
Adjust the drum's tuning, or change the drum head to a different type.