Short answerModerate1 mark
1(g)
Expand the following biological abbreviations:
ABA
Topic: ABA
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Answer
Exam answer
ABSCISIC ACID.
Explanation
Abscisic acid is the plant STRESS hormone. In drought it causes the stomata to CLOSE, conserving water; it also promotes leaf fall (abscission — hence the name) and induces seed dormancy.
It is the only one of the plant hormones that mainly INHIBITS growth, the others (auxin, gibberellin, cytokinin) promoting it.
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