Like DNA, RNA contains four nitrogenous bases. Three of them are the same as those found in DNA. The one that is different is called .
The five-carbon sugar in RNA is called .

Which of the following is a way that minerals are used? a. industry construction technology d. all of the above

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels

2. which is the last step in the scientific method?