Sickle cell anemia is persistent in the tropics because those with sickle cell anemia cant contract the malaria virus because of the shape of their blood cells, and this is advantageous in the tropics where there are more malaria cases. So those with sickle cell anemia live to pass on their genes.
The right answer is True.
A watershed is the expanse of territory drained by the waters of rivers and lakes, which in turn converge to a common outlet. Groundwater is flowing into the watershed, although the boundaries may not exactly coincide with surface water. Smaller flow areas that feed subwatersheds can be called catchment basins or drains. Watersheds can flow into river basins that may encompass larger areas.
Known watersheds are separated from one another by ridge lines, also known as watersheds. These are designed to delineate the watershed.
Watersheds are nested networks, the smaller ones nesting in larger ones. Streams that form the watershed can be organized according to a ranking framework. For example, the upper streams at the highest elevation of the watershed are first class streams.
When two first-class rivers meet, they form a second-rate stream. When two second-rate rivers meet, they form a third-class watercourse. A stream joined by another lower ranking stream retains its rank. For example, a third-class watercourse joined by a first or second-rate watercourse remains a third-rate watercourse.
1.) It is True that when a cell is put into an isotonic solution, individual water molecules cannot move back and forth across the cell membrane.
2) It is False that a when a cell is put into a hypertonic solution, there is a net movement of water molecules across the cell membrane into the cell.
3) It is True that when a cell is out into a hypotonic solution, there is net movement.
4) It is False that the movement of any solvent across a semi-permeable membrane is called osmosis.
