Stimulus–response in organisms: Movements due to light (phototactic/phototropic responses) are characteristically shown by which organism? Focus on simple motile protists in basic biology curricula. Choose the correct organism.

Difficulty: Easy

Euglena
Paramecium
Amoeba
Plasmodium

Correct Answer: Euglena

Explanation:

Concept / Approach
Euglena has a stigma (eyespot) and exhibits phototaxis (movement toward/away from light). While higher plants show phototropism, many school-level MCQs highlight phototactic movement in Euglena.

Why others are incorrect
Paramecium and Amoeba show taxes/kinesis to various stimuli but lack a distinct eyespot; Plasmodium is non-motile in this sense within the host.

Final Answer
Euglena shows light-directed movement.

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