The chart above shows the Mohs Hardness Scale for measuring the hardness of minerals. A mineral which can scratch Calcite, and can be scratched by Orthoclase is able to- can be scratched by both Talc and Diamond

scratch both Talc and Diamond

scratch Gypsum, and be scratched by Topaz

scratch Topaz, and be scratched by Gypsum

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).