1. <span>Any of a group of RNA viruses whose RNA is used as a template inside a host cell for the formation of DNA by </span>means<span> of the enzyme reverse transcriptase. The DNA thus formed is inserted into the host cell's genome. Most </span>retroviruses<span> can cause cancer. </span>Retroviruses<span> also include HIV.
2. </span>Prokaryotes<span> are 1-celled organisms that </span>do<span> not have a nucleus or any other membrane-bound organelles inside them. The name </span>prokaryote<span> itself actually lets you know that there isn't a nucleus, since pro </span>means <span>before and karyo refers to nucleus.
3. </span>Antibiotic resistance<span> occurs when </span>bacteria<span> change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The </span>bacteria<span> survive and continue to multiply causing more harm. </span>Bacteria<span> can </span>do<span> this through several mechanisms.</span>
I’m assuming the six kingdoms of life, but yes they do have a very large purpose for providing characteristics to bacteria, animals, fungi, humans, etc.
