There is only species of a koala but you can ask how many races there are.
The name is, "phascolarctos cinereus".<span />
Bacteria! Bacteria! Bacteria! :)
The epiglottis is a flap in the back of your tongue that prevents food from entering the larynx. When your mouth is closed, the epiglottis is in place and blocks the larynx opening. If your mouth is open, the flap lifts and the larynx is no longer blocked so you can breathe. This is why it's important to not chew with your mouth open... if you do, then food can go down the larynx by mistake.
Answer:
"The function of DNA is tied to its structure. ... The bonds between nitrogenous bases are essential to DNA's double helix structure, which resembles a twisted ladder. The base pairs form the rungs of the twisted ladder, and the sugar-phosphate strands form the sides."
Explanation:
- https://www.ancestry.com