<span>A prokaryote is a unicellular organism that belongs to either the domain Bacteria or the domain Archaea. Therefore, unlike a eukaryote, the prokaryote lacks in a nucleus and other organelles. The first organisms that appeared about 3.5 billions years ago were prokaryotes. They developed primitive forms of photosynthesis without oxygen as a waste. The first photosynthesizing prokaryotes appeared about 2.7 billion years ago which led to the changes in Earth atmosphere and consequently organisms dependant on oxygen could arise.</span>
The organ which plays the primary role in prompting individuals to seek food is the brain. The brain is one of the most important organ of the nervous system. It is comparable to the CPU of a computer. It is repsonsible of processing information that it is receiving from all the senses and send the message back to the organs for a response.
Http://www.pbs.org/wgbh/nova/cancer/folkman.html
I believe this website will help :)
B. Increased exposure to UV light increases the risk of mutation occurring.
Didn't mean to post this. sorry!