The correct answer is: stratosphere.
This is because their temperatures are rising instead of decreasing.
There are 4 primary layers of the atmosphere on Earth:
Troposphere (6-20km), the layer that we live in, where the weather occurs. Only nitrogen and oxygen present.
Stratosphere (20-50 km), where the airplanes fly, contains the ozone layer, which absorbs harmful radiation from the sun.
Mesosphere (50-85 km), the coldest region of Earth’s atmosphere (-100 C), protective layer
Thermosphere (80-690), the hottest (1500 C) and the thickest layer which consists of the ionosphere and the exosphere.
It indicates what elements is composed by and how many atoms of one element are linked to the other.
For example, this is the formula for table salt is:
NaCl
The formula indicates that table salt (sodium chloride) is composed by sodium (Na) and chlorine (Cl) on a 1:1 ratio.
Hope it helped,
BioTeacher101
Smooth muscles depolarize as a result of a transmembrane current of Calcium ions. When an action potential depolarizes the muscle cell membrane, it also travels into the body of the cell via the t-tubules. Unlike skeletal muscle, smooth muscle is dependent in two sources of calcium in order to intiate contraction. These two sources are calcium sequestered in the S.R. of the smooth muscle cell.