Self-study
A lichen is made up of a photosynthetic organism and a fungus growing in symbiosis on a solid surface. ███████ ██████ ████████ ████ ███ ███ █████████ ███ ████ ████ ███ ████████ ██ █████ ████ █████ ████ ██████ ███████ ███ ████████ ████ ███████ ████ █████████ ███ ████ ██████████ ██ █████ ██████████ █████████ █████████ █████ ██ ████████ ████ ████ █████████ ███ ██████ ████ ██ ███ █████████ █████████
Summary
A photosynthetic organism and a fungus growing symbiotically make up a lichen. Lichens absorb minerals from the air, rainwater, and the surfaces they grow on. Lichens cannot excrete elements they absorb.
Some types of lichen are vulnerable to toxic compounds, including toxins found in polluted air. These compounds can damage both the photosynthetic organism and the fungus that make up a lichen.
Strongly Supported Conclusions
Air pollution can have adverse affects on lichens growing in the area.
12.
Which one of the following ██ ████ ████████ █████████ ██ ███ ███████████ ██████
a
Lichens would not ██ ██████████ ██ █████ █████████ ██ ████ █████ ███████ ███ ████████ ████ ████ ███████
This answer is unsupported. We don’t know whether excreting toxic compounds would eliminate the harm these compounds can do to lichens.
b
The return of ███████ ██ █ ██████ █████████ ████ ███ ███ ███████ ███ ████████ ██████
This answer is unsupported. The stimulus only says that "some" lichens are vulnerable to poor air quality, so it's possible that non-vulnerable lichens could return to an area where air quality has not improved.
c
The absence of ███████ ██ █ ██████ █████████ ████ ███ ███ ██ ████████ ████████ ██ ████ █████
This answer is unsupported. There could be other variables besides air pollution that could affect the population of lichens. We cannot say if air pollution is the only factor that would eliminate lichens.
d
The photosynthetic organism ███ ███ ██████ ████ ████ ██ █ ██████ ███ ████ ██████ █████████████ ██ ████ ██████
This answer is unsupported. We only know from the stimulus how these organisms function symbiotically with each other.
e
Serious air pollution ██ █ ██████ ███ █████ ████████ ███ ████████
This answer is strongly supported. If toxic compounds found in polluted air can harm either or both of the symbiotic partners, then these compounds can have adverse effects for lichens.