Organisms that use the sun’s rays as an energy source and the atmosphere as a source of carbon are:    

The first organisms on Earth were:    

In the digestive system, the villi are:  

Most of the oxygen in human blood is carried:   

How do fungi obtain food?  

One type of bacterium that has a corkscrew shape and causes the disease syphilis is:    

Which of the following statement(s) is /are true?  

Which of the following events happens first in vertebrate development?  

A difference between a morula and a blastula is that:    

Which combination of gland and hormone would be linked to winter hibernation and spring reproduction in bears?