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Difficulty: HardLogical Inferences

In many alpine plants, the synthesis of anthocyanin pigments is upregulated in response to intense ultraviolet-B (UV-B) radiation, serving as a photoprotective shield. Biologists hypothesized that this response is purely plastic, triggered solely by direct exposure. However, in a recent study, researchers grew offspring of alpine plant populations under uniform, low-UV-B greenhouse conditions. Offspring whose parents had experienced high wild UV-B exhibited significantly higher baseline anthocyanin levels than did offspring of parents from low-UV-B environments, despite neither offspring group encountering UV-B. Which choice most logically completes the text?

  1. A
    all alpine plant species possess the capacity to transmit environmental adaptations to their offspring.
  2. B
    offspring of parents from low-UV-B environments are incapable of producing anthocyanins when exposed to UV-B.
  3. parental exposure to UV-B radiation can influence the baseline production of photoprotective pigments in offspring that have not themselves been exposed to UV-B.Answer
  4. D
    alpine plants grown under low-UV-B greenhouse conditions will eventually lose their ability to synthesize anthocyanins entirely.

Answer

parental exposure to UV-B radiation can influence the baseline production of photoprotective pigments in offspring that have not themselves been exposed to UV-B.
The correct option is supported because the experiment shows that offspring whose parents experienced high wild UV-B exhibited higher baseline anthocyanin levels than did offspring of parents from low-UV-B environments, even though neither group of offspring encountered UV-B radiation. This directly demonstrates that the parents' exposure to UV-B has an effect on the baseline pigment levels of their offspring.

Step-by-Step Solution

1
Analyze the premises and findings presented in the text.
The text states that anthocyanin upregulation is a response to UV-B. A study compared offspring grown in uniform low-UV-B conditions. The offspring of parents exposed to high wild UV-B had higher baseline levels than those from low-UV-B parents, even though neither offspring group experienced UV-B.
To understand the relationship between the parental environment and the offspring's characteristics.
2
Determine what logical conclusion must follow from these premises.
Since the only difference between the two offspring groups was the parental environment (high vs. low UV-B) and they themselves did not experience UV-B, the difference in their baseline anthocyanin levels must be due to the parental exposure to UV-B.
To connect the experimental setup and results to a valid, non-speculative inference.
3
Evaluate the choices to find the one that matches this conclusion.
The option stating that parental exposure to UV-B can influence the baseline production of these pigments in unexposed offspring directly reflects this finding.
To select the option that is fully supported by the text without introducing external assumptions or generalizations.

Key Concept

Logical Inferences
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Topics

Logical Inferences

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