Which is characteristic of a mineral?

a.
it must be man-made and crystalline.

b.
it must be naturally occurring and crystalline.

c.
it must be man-made and amorphous.

d.
it must be naturally occurring and amorphous.

Anton created a chart listing different types of materials. which best complete the chart?

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.