Both plant cells and animal calls contain mitochondria and yet there were not visible in the cells you viewed in this lab. Does this mean that these organelles are not found in cheek and onion cells? Why or why not?

the answer is b.) hydrogen bonds between bases.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.