Down syndrome is a condition in which the individual

a. has three copies of chromosome 21.

b. has three copies of chromosome 23.

c. lacks chromosome 46.

d. has only one chromosome 21.

Where does most exogenous antigen presentation take place?

Gap junctions (electrical synapses) A. are found only in a few species of animals. B. are far more numerous than chemical synapses. C. have larger pores than voltage-gated ion channels have. D.

Sketch and label a food-web that includes at least 6 different items. Make sure to have the arrows show how energy flows from one trophic level to the next.

What agent of erosion creates a cirque?

The proximal and distal ends of a long bone are called the

Chimpanzees reproduce sexually, and sponges reproduce asexually. What disadvantage do chimpanzees have compared to sponges

What is the immune system? A. The group of cells and organs that protect the body from disease. B. A group of cells that undergoes apoptosis to protect the body. C. A group of organelles that digest particles that invade the cells. D.

Seth runs up 3 flights of stairs. the first climbs takes him 12 seconds. his second climb takes him 15 seconds. Has the power done been affected?

What is the best description of a molecule

What are Designer Babies? What are the pros and cons?