Which layer of Earth's atmosphere merges with the vacuum of space?
O
A. Stratosphere
O B. Exosphere
O C. Thermosphere
O D. Troposphere
SUBMIT

Option B. Exosphere.

Explanation:

Exosphere is the last layer of atmosphere which is present at the height 700 to 10000 km from earth surface. This layer is thin as compared to other layers of the atmosphere. The layer of exosphere is composed of two elements i. e. helium and hydrogen. The temperature of exosphere is 1700 degree Celsius at daytime and becomes cold at night.

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!

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms