Answer: a hard sedimentary rock, composed mainly of calcium carbonate or dolomite, used as building material and in the making of cement.
Animal cells do not have cell walls because they do not need them. Cell walls, which are found in plant cells, maintain cell shape, almost as if each cell has its own exoskeleton.
Answer:
Cell membrane
Explanation:
The cytoskeleton is known to be a kind of proteinous filaments which is found in the cytoplasm of organism but grow out to the cell membrane to give shape to the organism and likewise help in movement.
In the case highlighted above, the organism might still not be able to get a shape especially when the cell membrane is affected or being damaged.
<u>ANSWER</u>:- option A formation of fossil fuels.
<u>Explanation</u>:-
- Fossil fuels are formed from dead and decaying plants and animal.
- When the dead and decaying plants and animals are exposed to heat and pressure over a long period of time they get converted to oil, coal, gas etc.
- These oil ,coal, gas are called as fossil fuels.
- The entire process of formation of fossil fuels can take place over a million of years.
- In contrast to the formation of fossil fuels , the process of photosynthesis in plants, respiration in animals and emission of waste is a phenomena which occurs at daily basis and over a short interval of time.
So, <em>the formation of fossil fuels is the phenomena which takes the longest time in the carbon cycle.</em>
