<h2>Answer:</h2>
Mesosphere
<h2>Explanation:</h2>
The atmospheric layer that protects the Earth against danger of the rocks is the mesosphere. This layer is above the stratosphere. The temperature drops in this layer to about -100 degrees Celsius. This is the coldest region of the atmosphere. The mesosphere burns up most meteors and asteroids before they are able to reach the earth's surface. It becomes cold enough to freeze water vapor in its atmosphere into ice clouds.
Answer:
An RNA molecule transcribed from DNA is called messenger RNA, or mRNA for short. The mRNA now moves away from the DNA and leaves the cell's nucleus. Outside the nucleus, ribosomes attach themselves to the RNA.
Explanation:
In negative control, a gene is switched off when a regulatory protein binds to DNA and shuts down transcription.
B.
It allows some substances to pass through but blocks the passage of others.