Answer:
Each electron carrier alternates between being reduced and being oxidized.
Answer:
The condition of the Earth had to become favourable before it could support any form of life.
The formation of the different layers around the earth like the ozone layer was necessary before life could originate. Primitive species such as some prokaryotes were able to live in hydrothermal conditions during the initial times. With the passage of time, as the concentration of oxygen increased due to photosynthetic prokaryotes, situations became favourable for eukaryotic organisms to arise.
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).
Answer:
Explanation:
nucleus: the center of the cell that contains the genetic material. The nucleus is like the "Brain" of the cell.
ribosome: is a large complex of RNA and proteins. Ribosomes are the cell structures that make protein. They are found in the endoplasmic reticulum.
endoplasmic reticulum: a network of tubular membranes in the cytoplasm. They fold protein molcules in sacs and transport these proteins in vesicles to the golgi apparatus.
Golgi Apparatus: stores and modifies proteins and prepares to transport them to different parts of the cell.
I hope this helps.
