Viruses need to be inside a living thing (of course the living thing has to have the right temperature which most living things do) . When they're inside a living thing they start injecting the host's cells with its DNA in order to make more copies of itself which allows the virus to spread. So basically viruses need to be inside something living.
There are sometimes similarities in the embryonic stages of organisms that do not exist in the adult stages.
I believe that both flatworms and roundworms have a body type called Bilateral symmetry. Animals that are bilaterally symmetric have mirror symmetry in the sagittal plane, which divides the body vertically into left and right halves, with one of each sense organ and limb pair on either side.
My neighbor has one that screams its hilarious!
Answer:
Nitrogen is the most commonly limiting nutrient in plants. Legumes use nitrogen fixing bacteria, specifically symbiotic rhizobia bacteria, within their root nodules to counter the limitation. Rhizobia bacteria convert nitrogen gas (N2) to ammonia (NH3) in a process called nitrogen fixation.
