Which areas of the ocean experience the greatest variation in salinity?

Of the five ocean basins, the Atlantic Ocean is the saltiest. On average, there is a distinct decrease of salinity near the equator and at both poles, although for different reasons. Near the equator, the tropics receive the most rain on a consistent basis. Oceans and seas cover roughly 70 per cent of the world, and contain about 97 per cent of the Earth's water, and yet, the water is undrinkable due to the salt levels

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

a. the production of carbon dioxide through the process of photosynthesis