Down syndrome is caused by trisomy 21, the presence of three copies of chromosome 21. the extra copy usually results from nondisjunction during meiosis. in some cases, however, the extra copy results from a translocation of most of chromosome 21 onto chromosome 14. a person who has had such a translocation in his or her gamete-producing cells is a carrier of familial down syndrome. the carrier is normal because he or she still has two copies of all the essential genes on chromosome 21, despite the translocation. however, the same may not be true for the carrier’s offspring.

Size and shape of continents

If these are the missing choices: a. to determine skin temperature, place the back of your hand against the patient's skin.b. determine body temperature by touching the patient's hands and feet.c. skin temperature will tell you very little about this patient's condition or well-being.d. the patient's skin temperature and color will likely be warm and red.my answer is: a. to determine skin temperature, place the back of your hand against the patient's skin. using the back of the hand to check for temperature rather than the palm is more effective because the back of the hand has more nerves that can feel and transmit the temperature than the palm.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.