The scratch test.
The scratch test is used by scientists and people who study rocks and minerals to determine the strength of the rock. They have the scratchers numbered one through ten and scratch the rock or mineral until the scratcher makes a mark in the mineral then they know the strength of the rock.
Answer: Asexual reproduction
For example, sexual reproduction allows for variation, but gestation usually takes a long time and it requires heavy parental input. Asexual reproduction occurs quickly, but because all of the offspring have the same genetic information, individuals are more susceptible to disease.
Explanation:
Bicarbonate buffer system. Human blood contains large amounts of carbonic acid, which is a weak acid, and bicarbonates, a strong base. If blood pH falls below 6.8 or rises above 7.8, one can become sick or die. This bicarbonate buffer system help maintain blood pH at 7.4. The bicarbonate neutralizes excess acids in the blood while the carbonic acid neutralizes excess bases.
Enzymes separating DNA molecules.