<span>Mitosis is a part of the cell cycle in which chromosomes in a cell nucleus are separated into two identical sets of chromosomes, and each set ends up in its own nucleus.</span>
Answer:
A) Times of major climate change
Explanation:
The geological time scale is based on major changes in Earth's climate history. This is because of the reason that climate governs the geological processes on Earth. In geology, we study the ages with the help of stratigraphical data where sediment deposition and the fossils it is hosting are the keys to understand the environmental conditions at that particular time. These conditions didn't change significantly unless the climate was changed. An example is the extinction of dinosaurs during K/T boundary event (mass extinction). The most likely reason is the hitting of a meteorite on Earth that changed the climate of Earth in a short period making it least favorable for many organisms to survive.
On the other hand, the occurrence of huge events cannot be used to establish a geological time scale because sometimes, the changes happen more slowly.
Similarly, shifts in the Earth orbits are cyclic however geological time scale doesn't reflect cyclic changes. The same climate can establish in different ages but these events are not used not as a criterion to establish a geological time scale.
In the end, the time span of humans on Earth is very small when compared with the overall geological time scale. Humans record exists from Pleistocene (2,580,000 to 11,700 years ago) to today whereas geological time scale starts in the Archean Eon (4.0 billion to 2.5 billion years ago).
................... and living organism together make up THE SOIL.
Soil is the uppermost layer of the earth in which plants grown. It usually have a dark or brown coloration as a result of the decaying organic materials which it contains. There are different types of soil depending on the type of particles which they contain, but the best soil for agriculture is loamy soil.<span />