<span>Individual cells, as well as organisms, must maintain homeostasis in order to live too. One way that a cell maintains homeostasis is by controlling the movement of substances across the cell membrane.</span>
The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
Answer:
Original strand is the old strand and replicated strand is new strand.
Explanation:
DNA is replicated by the semi-conservative way which means the new strand is replicated over the old strand and one DNA duplex has one new strand and one old strand. So the original strand is the old strand and the replicated strand is the strand that is synthesized over the original strand.
In DNA the replicated strand is made by adding nucleotides complementary to the opposite nucleotide present in the template or original strand. Adenine and thymine make complementary base pairing with each other and guanine and cytosine makes complementary base pairing with each other.
Answer:
The preferable option will be - A.
A. similar environments and specific traits increased their chances of survival.
Explanation:
- The shark and dolphins have similar body shape and fins. But shark is a fish and dolphin is a mammal.
- Both of them are exposed to similar kind of environments. Both of them possess a specific kind of alternative characters and traits.
- So, Some species may have similar body structures even if they are not related because they evolved in similar environments and specific traits increased their chances of survival.
Answer:
1.true2.true3.true
Explanation:
sorry not sure about this answer
