This is an experiment where the researcher manipulates one variable, and control/randomizes the rest of the variables. It has a control group, the subjects have been randomly assigned between the groups, and the researcher only tests one effect at a time.
<span>All of their skulls were fairly long with sharp teeth.</span>
Answer:
B: only amino acids join together with peptide bonds to form proteins.
1. One reason is extinctions happen because of some kind of change in the environment where a life form lives. While some species can adapt to the changes, others die, and if enough die, the species becomes extinct. These are some of the biggest factors in the extinctions of particular species. 2. Contaminants in the environment, such as pesticides.
