Answer : The correct option is, (b) 22.5 M
Explanation : Given,
Mass of calcium nitrate tetrahydrate = 266 g
Molar mass of calcium nitrate tetrahydrate = 236.15 g/mole
Volume of solution = 
Molarity : It is defined as the moles of solute present in one liter of solution.
Formula used :

Now put all the given values in this formula, we get:

As calcium nitrate tetrahydrate dissociate to give 1 mole of calcium ion, 2 moles of nitrate ion and 4 moles of water.
The concentration of nitrate ion = 
Thus, the concentration of nitrate ion is, 22.5 M
<span>Now consider a low pressure area on a disk as shown below.A parcel of air at point A would move toward the center of the low pressure area. That movement would take it farther away from the center of the disk and therefore it would move to the west. A parcel of air at B would move toward the center of the low pressure area which would also take it closer to the center of the spinning disk where its speed is greater than the surrounding points. It would appear to move to the east. With A moving to the west and B moving to the east the line from A to B is rotating counterclockwise.</span>
The answer to this question would be true.
Reducing acidity of chyme :Acidic chyme entering the duodenum stimulates the release of secretin from the small intestinal glands.
Answer:
Many areas of the United States experience explosive population growth. <u>The more people that reside someplace, the more demand there is for water there.</u> Often these urban-growth <u>expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater.</u> <u>The stress often depletes groundwater supply, thereby causing wells to dry up.</u> Then water must be brought from somewhere else to support the local population.
Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.
<u>Human activities affect groundwater quality.</u>
<u>Here are some sources </u>and possible solutions to groundwater pollution:
<u>Agriculture</u>—Reduce usage of pesticides and fertilizers.
<u>Landfills</u>—Monitor for leakage and repair linings.
<u>Underground storage tanks</u>—Remove damaged and unused tanks.
<u>Household wastes</u>—Properly dispose of household hazardous waste.
<u>Septic tank leaks</u>—Properly maintain and repair tanks.
Explanation:
This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.