Neco 2018 Biology Question 47

Practice objective / multiple choice question 47 from the 2018 Neco Biology examination.

Neco 2018 Biology Objective / Multiple Choice Hard Difficulty

Question 47 NECO • 2018 • BIOLOGY • objective

In an experiment, three groups of identical bean leaf discs were incubated for 30 min under identical light conditions. The mean stomatal aperture measured (\(\mu\text{m}\)) were: Control (0 \(\mu\text{M}\) ABA): 2.4, 5 \(\mu\text{M}\) ABA: 3.6, 20 \(\mu\text{M}\) ABA: 2.8. (a) Which treatment gives the greatest stomatal opening? (b) Calculate the percent increase in aperture for that treatment relative to the control. (c) Based on these results, which statement is best supported? (i) ABA inhibits stomatal opening at all concentrations, (ii) ABA stimulates opening at low concentrations but inhibits at high, (iii) ABA has no effect.

A. 20 µM, 17%, statement i

Correct Answer B. 5 µM, 50%, statement ii

C. 5 µM, 30%, statement iii

D. 0 µM, 0%, statement i

Correct Answer

Correct Option:

5 µM, 50%, statement ii

This is Neco 2018 Biology Question 47. It is one of the objective questions from the 2018 Neco Biology examination.

Difficulty level: Hard .

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