Amber has written the following prediction: "if a rock is put under a great deal of pressure, then the minerals in the rock will chemically change." what is the independent variable used in an investigation to test this prediction? a. the amount of pressure placed on the rock b. the type of minerals used to form the rock c. the number of rocks tested d. the chemical composition of individual minerals

The independent variable is the variable we have full control over or we could manipulate. Thus, from among the choices below:

A. the amount of pressure placed on the rock B. the type of minerals used to form the rock C. the number of rocks tested D. the chemical composition of individual minerals

The answer is A. (the amount of pressure placed on the rock). It is the independent variable.

ans.

dna fingerprinting is defined as a process that determines the dna characteristics of an individual. these dna characteristics are unique among individuals as their fingerprints, so it is known as dna fingerprinting.

steps of dna fingerprinting includes extraction of dna from sample, amplification of dna, restriction digestion of amplified dna, and then analysis of dna by gel electrophoresis, respectively.

thus, the next step performed by the scientist is 'to cut the amplified dna (obtained by polymerase chain reaction) by restriction enzymes that cleave the dna into fragments and their analysis.'