Answer:
species
Explanation:
According to the most widely used species definition, the biological species concept, a species is a group of organisms that can potentially interbreed, or mate, with one another to produce viable, fertile offspring.
Even if a microorganism is a part of the normal microbiota of a human being, it may cause the death of the person. For example, say E. coli, it resides in intestines and is harmful. But, if its number increases way too large, it may cause infection (Colitis) and even death. So, even the normal microflora needs to be present in the controlled quantities, inside the body.
RNA.
Explanation: nucleic acid makes up both RNA and DNA.
Yes oceanic crust is denser than continental
