Why does limiting exposure to carcinogens reduce the risk of cancer?
1. reduces the rate/incidents of genetic mutations
2. helps the body maintain an effective immune system
3. helps the body regulate internal chemistry, for better elimination of naturally occuring cancer cells
4. reduces the body's production of chemicals that promote the development of cancer cells

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."

the electromagnetic energy from the sun arrives in the form of visible and invisible light.

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation: