Which of the following is NOT a constraint that a wheelchair has as an assistive device? A.
Wheelchair materials have to be lightweight but durable.
B.
Wheelchairs are usually not brightly colored.
C.
Wheelchairs are not easy to operate in sand or snow.
D.
Wheelchairs are not particularly useful for navigating stairwells.

There are few cells in the body that do not undergo mitosis: most somatic cells divide regularly, some more than others. take for example the cells that line the digestive tract. these cells must be frequently replaced because they are constantly eroded by the movement of food through the tract. what mechanism(s) is/are in place to ensure that these cells are exact copies of the mother cell