1. A normal cell in a laboratory forms a single layer on a dish. When the cell touches other cells, it halts dividing. Which of the following hypotheses explains this phenomenon? a. It was regulated by kinases and cyclins.

b. Cells grow and divide in response to one growth factor.

c. It happens when internal and external signals stimulate genes that help produce self-destructive enzymes.

d. Receptors on adjacent cells have bound to each other causing the cells’ cytoskeleton to form structures that may hinder the signals that activate the growth.

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.

i would have a lunch. it's one big package of food, making it one food. : p

i believe the answer would be b. hope it : )