One property that makes ddt hazardous over the long run is that ddt is
a. an insecticide.
b. a perfect pesticide.
c. subject to biological magnification.
d. deadly to herbivores.

C. subject to biological magnification.  

Explanation:

DDT is an insecticide that exhibits slow metabolism and excretion. The slow breakdown of DDT causes it to accumulate in fat tissues of organisms. Biological magnification refers to the process of increased concentration of toxic chemicals in the tissues of living beings of higher tropic levels. The accumulated higher concentration of DDT poses harmful effects on the health of top consumers.

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.

the answer is c on e2020, bud.