Algae are small photosynthetic organisms found in aquatic ecosystems. As algae grow, they produce and store a carbon-rich oil in their cells. Up to 40% of their body mass can be taken up by oil. Scientists discovered a way to extract the oil to create algae fuel, a biofuel that can be used in place of fossil fuels. Scientists expected that algae would be able to produce up to 60 times more oil per acre than plants, like corn, that are commonly used to produce biofuel.

To commercially produce algae oil, very large ponds for algae growth were constructed. However, scientists soon made two discoveries.
As the algae grew on the ponds, they crowded and shaded one another.
Many insects and other consumers frequently entered the ponds.
Why would these be a problem for algae oil production?
A.
Consumers feed on algae, so they cause the energy stored in algae oil to be permanently lost from the environment.
B.
Shading reduces access to sunlight, so algae produce fewer sugars and are less able to store energy in the oil.
C.
Insects feed on algae, so they cause all of the energy stored in algae oil to be converted back into light energy.
D.
Crowding reduces access to food, so it makes algae less able to take in the sugars needed to produce oil.

B

Explanation:

Let's try to eliminate answer choices.

A) "Consumers feed on algae, so they cause the energy stored in algae oil to be permanently lost from the environment." The incorrect part here is that it says the energy is "permanently lost from the environment", but this is not true. All energy is constantly being recycled and by the Law of Conservation of Energy, energy cannot be destroyed or "lost".

B) "Shading reduces access to sunlight, so algae produce fewer sugars and are less able to store energy in the oil." This is correct.

C) "Insects feed on algae, so they cause all of the energy stored in algae oil to be converted back into light energy." This is incorrect because it says that all the energy is converted back into light energy. However, if insects eat the algae, it's not possible for that energy to become light energy; light energy can only come from the sun.

D) "Crowding reduces access to food, so it makes algae less able to take in the sugars needed to produce oil." This is incorrect because the algae doesn't take in sugar; it produces the sugar.

Thus, the answer is B.

Hope this helps!

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;

the correct answer is d