Answer:
Number of bacteria required 
Explanation:
Given -
Size of each bacterium 
micrometers long
These bacteria are arranged end to end.
The size of chain to be formed is equal to 
centimetres
Let us say that in forming a chain of centimetres nearly X number of individual bacterium are required.
hence, number of bacterium required to form centimetres chain can be represented as
Number of bacteria required
Answer:
A.because dna is our blood not sure
Answer:
it was part of the ocean it needs water
Answer:
Primary succession is one type of the ecological succession which takes place on the land devoid of vegetation or barren land.
The species which first flourishes on this barren land are known as pioneer species which includes the species of bryophytes and pteridophytes like lichens and mosses.
These lichens and mosses help breakdown the barren rocks through chemical leaching and help increase the nutrient content. This allows the ferns and small pteridophytes to grow.
Then the area is colonized by the intermediate species which includes herbs, shrubs later trees. These intermediate species help attract the animals and thus help establish the biological community.
Thus, Lichens mosses → herbs→ shrubs →trees.
