Read the following statements and answer the question that follows.

A. Whatever that might be on Europa—far from the Sun, and beneath kilometers of ice
—it will not be sunlight.
B. The final ingredient for a habitable world is a source of energy for life to exploit.
C. On Earth almost every living thing ultimately depends on photosynthesis for its
energy, including the rich ecosystems in the ocean depths, discovered in the 1980s and
which helped the idea of life on Europa gain a foothold.
D. Their inhabitants do not benefit from sunlight directly, but their metabolisms are
powered by chemicals created in the photosynthesizing, oxygen-rich surface oceans
far above.
E. That is a bit of a problem.

Which of the following sequences is the MOST logically ordered?

We need to arrange the sentences in a logically sequenced order; to do that, we need to get an idea of what the particular paragraph will be about. So, we look at the sentences and we see sentence C: On Earth almost every living thing ultimately depends on photosynthesis for its energy, including the rich ecosystems in the ocean depths, discovered in the 1980s and which helped the idea of life on Europa gain a foothold.
We realise that the paragraph is referring to energy and living organisms and ecosystems.
We see that, D and E are abrupt sentences to start a paragraph with, they obviously need previous context and reference. A
Starting with A would abruptly introduce Europa's sunlight issue without first providing the necessary context that a habitable world needs an energy source, making the discussion lack a clear foundation.
Between C and B, B seems like a much more suitable options to start a paragraph with, where it introduces the concept of Energy needed for a habitable world. 

We look at the option that starts with B, which is B, A, E, C, D

Following B, A specifies the particular energy challenge on Europa, linking the general need for energy to a specific case: lack of sunlight on Europa.
E reacts to the challenge presented in A, acknowledging the issue created by the absence of sunlight, maintaining logical flow.
C introduces an Earth analogy, explaining how life adapts in deep-sea environments away from sunlight, offering a possible parallel for Europa's situation.
Finally, D elaborates on the mechanism behind these deep-sea ecosystems, completing the explanation and connecting back to the possibility of life on Europa.

The sequence B-A-E-C-D moves from the general requirement of an energy source (B), through the problem of no sunlight on Europa (A, E), to an analogous Earth scenario (C, D) that suggests how life might thrive without direct sunlight, creating a coherent narrative.