Why do eukaryotic cells require mitochondria?

Which promotes sustainability? o a. using more landfills o b. finding new sources of coal o c. increasing consumption o d. encouraging recycling programs

Which muscle cell structure stores calcium ions that are used to trigger the contraction?

How do you suppose living conditions differ between the country furthest along in the demographic transition compared to the country earliest in the transition? how would living conditions in these two countries affect both birth and death rates?