The number of hedgehogs on a hill would be considered a community.
a. true
b. false

Archaebacteria use for movement. celia flagella pili cell walls

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

In which part of the body is a ball-and-socket joint found?