What is the term for the breakdown of glucose in the absence of oxygen?

Fermentation

Explanation:

In the absence of oxygen, the cell uses a process called fermentation. Fermentation doesn't break the sugar down any further, it simply helps reset the system so that more sugar can be broken down.

Because aerobic respiration breaks the sugar all the way down, it releases much more energy than fermentation.

Hope this helps :)

Bats use ultrasounds. When an ultrasound encounters an obstacle it goes back to it's source - bat (echo). Since they are active during night this way of "scanning" surroundings is very handy.
Bats have good sight btw.