Because to actually use the word evolve an organism must suffice more than one condition, which in this case would be an advantageous trait. Having an advantageous trait (from our eyes at least) must also include the right and stimulating enviironment for procreation. So this answer is multifolded.
Microhabitats promote biodiversity because they create more niches for organisms to adapt to. ...
The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition.
Well the only organelle that produces ATP/cellular energy is the mitochondria so via process of elimination you would conclude mitochondria are most abundant in muscle cells.
