Nutrients
All microorganisms need food. The food sources can vary, but the organisms primarily extract carbon and nitrogen from substances such as proteins, fats and carbohydrates. Some microorganisms seek out and absorb such particles. Others may perform chemical reactions with surrounding elements such as carbon dioxide to gain what they need, while still others can produce their own simple sugars through photosynthesis similar to plants. Nitrogen, which is used to synthesize proteins, can be taken from the surrounding atmosphere or from other organic matter.
Temperature
In general, the higher the temperature, the more easily microorganisms can grow up to a certain point. Very high and very low temperatures both obstruct the enzyme processes microorganisms depend on to survive, but individual species of microorganisms have grown to prefer different levels of temperature. Scientists usually divide them into three different groups: psychrophiles, mesophiles and thermophiles. Psychrophiles prefer temperatures from 0 to 5 degrees Celsius; mesophiles like it in the middle, 20-45 degrees Celsius; and thermophiles like it hot, thriving in temperatures around or above 55 degrees.
pH Levels
Microorganisms also prefer a certain pH level in the substance or environment in which they grow--that is, they prefer to have particular acidic qualities in their surroundings. Most microorganisms, including most human pathogens, are neutriphils, organisms that prefer a neutral pH level. Some like high pH levels, but most often, if conditions are too acidic, then the organism's enzymes break down.
Moisture
The free flow of water is vital to microorganisms for their cells to exchange materials and for their metabolic processes. All microorganisms require some level of water, but a few can survive in low-moisture conditions by conserving all the water they find and by staying in a moisture-rich environment. As a general rule, though, the more moisture, the more microorganisms there will be found.
Elements Present
That looks like cells of a multicellular organism, so B.
Explanation:
2. First we have to calculate the heat gained by the solution.
where,
q = heat gained = ?
c = specific heat of solution = 
m = Mass of the solution = 100.0 g
= final temperature
= initial temperature
ΔT = 
= 5.6°C
Now put all the given values in the above formula, we get:
The amount of heat energy gained by the solution 2,340.8 J.
3.
Heat gained by solution = Heat released on neutralization reaction
2,340.8 Joules is the value 
of reaction for the neutralization reaction described in number 2.
4. 
Moles of phosphoric acid = n
Volume of the phosphoric acid solution = 50.0 mL = 0.050 L
Molarity of the phosphoric acid solution = 0.60 M
0.03 moles of phosphoric acid are contained in 50.0 mL of 0.60 M phosphoric acid solution.
5. To calculate the enthalpy change during the reaction.
where,
n = moles of phosphoric acid = 0.03 moles
= enthalpy change = ?
q = heat gained = 2,340.8 J = 2.3408 kJ
Therefore, the enthalpy change during the reaction is -78.027 kJ/mole
