Self-study
Certain bacteria that produce hydrogen sulfide as a waste product would die if directly exposed to oxygen. ███ ████████ ███████ ██████ ████ ███████ ████████ ██ ███ ██ ██████████ ██ ████ ███████ ███ █████████ ████████████ ███ ████████ ███████ █████ ██ ████ █████ █████████ ██ ███ █████ ███████ █████████ ███ ████████ ████ █ ██████ ██ █████ ██ █ ███████ █ █████ ██████ ██ █████ ████████ ████████ ███ ██████ ██ ███████████ ██ █████ ██ ███ ████████ ██ ██████ █████████████
Summary
Some bacteria that produce hydrogen sulfide as a waste product would die if exposed to oxygen. The hydrogen sulfide produced removes oxygen from the bacteria’s surroundings by reacting with it. Hydrogen sulfide also kills other organisms which the bacteria use as a food source. Therefore, a dense colony of these bacteria can thrive indefinitely.
Strongly Supported Conclusions
A dense colony of these bacteria will indefinitely produce enough hydrogen sulfide to kill surrounding organisms for food and prevent oxygen from coming into contact with the bacteria.
23.
Which one of the following ██ ████ ████████ █████████ ██ ███ ███████████ ██████
a
A dense colony ██ ███ ████████ ███ ████████████ ████████ ██ ███████ ██████ ████████ ███████ ██ ████ █████ █████████ ██ ███ ████ ███ ██ ███████ ██████ ████ ███████ ███ █████████
This answer is strongly supported. If the colony is to survive indefinitely, it must be that they will produce enough food for themselves in the form of other organisms and prevent oxygen from coming into direct contact with the colony.
b
The hydrogen sulfide ████████ ██ ███ ████████ █████ █████ █████████ ██ ███ ████ ██ ████████ ████ ███ ████████ ███████
This answer is unsupported. We don’t know from the stimulus how the other organisms in the bacteria’s environment are killed from the hydrogen sulfide. There could be another way than by removing oxygen in the environment.
c
Most organisms, if ██████ ██ ███ ████████ ███████ ████████ ██ ███ █████████ ███ ███████ █ ██████ ██ ████ ███ ███ █████████
This answer is unsupported. Saying “most” organisms is too strong. We only know that there must be some organisms that the hydrogen sulfide kills in order to produce a food source.
d
The bacteria can ████████ ██ ██████ ████████████ ████ ██ ██ ███████████ ██ █████ ███ ████████ ███████ ████ ███████ ███ ███████ ███ ██████ ███ ██████ █████ █████████ ██ ███ █████
This answer is unsupported. We only know that hydrogen sulfide can create environment where the bacteria can thrive. However, we don’t know if hydrogen sulfide is the only way to produce oxygen-free, food-rich conditions.
e
If any colony ██ ████████ ████████ ████████ ███████ ██ █ █████ ████████ ██ ███████ ███████ ████ ██ ██ ████ ████████ ████ █ ██████ ██ ████ ███ █████████ ████ ████ ██ ███████
This answer is unsupported. The stimulus tells us that hydrogen sulfide production can protect and provide food for bacteria, but not that it's guaranteed to do so.