What kind of air masses form over land? maritime air mass polar air mass continental air mass tropical air mass

The correct answers are:

- Polar air mass;

- Continental air mass;

The polar air masses form predominantly over land, or rather ice. They form over the poles and their close proximity, with the ones forming on the south pole being formed directly over Antarctica as a land mass, while the ones on the north pole being formed over ice, or rather the frozen ocean. They are very cold and very dry air masses.

The continental air masses form above land, deeper into the mainlands of the continents, which is why that have this name. They can be either very cold and dry in winter, or very hot and dry in the summer.

the statement is true

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!