Howard is making a class presentation about the process of abrasion and he wants to model the process. Which of these can Howard do to model the
process of abrasion?

A. Pour water over a pile of sand

B. Rub a soft rock on a rough surface

C. Put flat iron fillings in a beaker of water

D. Place a Few small drops of acid on a rock.

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies

b.have there own function.