John and Jane are planning a family, but since each has a brother who has sickle-cell disease, they are concerned that their children may develop sickle-cell disease. Neither John, Jane, nor their respective parents have the disease. They consult a genetic counselor who tells them that .
a) there is no chance that any of their children will have sickle-cell disease
b) all of their children will have sickle-cell disease
c) one of four of their children can be expected to have sickle-cell disease
d) it's possible that none of their children will have the disease, but blood tests on them both will be required to make sure
e) it is impossible to tell whether their children will have the disease

D

Explanation: They can be sure if they both take a blood test. There is a possibility both jane and john are carriers of sickle cell(AS), which makes it possible to have children with sickle cell disease. Also, both jane and john may not be carriers at all (AA), in that case none of their child will have sickle cell, likewise if either of them is AA, and the other is a carrier, none of their child will have sickle cell.

hello

answer: collecting information/data

reason: the student is going around and asking people questions to collect data

i hope this

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!