In klinefelter syndrome males have chromosomes xxy. this is an example of:

a.) non-disjunction of sex chromosomes

b.) crossing over

c.) chromosomal rearrangement

Based on the topographic map of mt. st. helens, what is the contour interval of the volcano about height is 2,950 m?

The most effective way to provide children with safety messages is to

What is point source pollution of an aquatic ecosystem? a) pollution of freshwater sources b) pollution from many sources that combine into one c) pollution that occurs over a wide area; water that runs off from fields, parking lots, and other land surfaces d) pollution that can easily be identified with a single discharge source, such as an open pipe which drains into a body of water