Using the prefix micro- and using what you know about meteoroids, which description below would best fit?

Hello. This question is incomplete. The full question is:

"Using the prefix micro- and using what you know about meteoroids, which description below would best fit?

A. a large particle of dust or rock moving at slow speeds through space.  B. a small particle of dust or rock moving at fast speeds through space.  C. a large particle of dust or rock moving at fast speeds through space.  D. a small particle of dust or rock moving at slow speeds through space."

B. a small particle of dust or rock moving at fast speeds through space.

Explanation:

Micrometeoroids are small particles of dust or rock, smaller than asteroids, sometimes smaller than an atom, and that roam in space at high speeds. Depending on the diameter of a micrometeoroid, it can reach speeds close to the speed of light.

Micrometeoroids are fragments that have been released from an asteroid or from another rocky celestial body. They are a concern for astronauts who can be reached by them.

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!

geologic time scale (for gradpoint) =)