Question

A student had heard in his biology class that placing a ripe apple into a closed container with an unripe fruit would cause the unripe fruit to ripen. The student set up an experiment in which an unripe banana was placed into a paper bag. A second unripe banana was placed into a separate bag with a ripened apple and sealed shut. Both bags were allowed to sit undisturbed at room temperature for 48 hours. The student noted that after 48 hours, the first banana was still green and unripe. The second banana was yellow and soft to the touch.
Which statement best represents a conclusion the student might reach?

• A. The banana emitted a substance that caused it to ripen in the presence of the apple
• B. The apple emitted a substance that caused the banana to ripen in its presence.
• C. The banana began to decay in the presence of the apple which is why it softened.
• D. The banana ripened quickly overnight on its own despite the presence of the apple.
• E. None of the above are valid conclusions the student could reach.

Answer 1

The correct option is B The apple emitted a substance that caused the banana to ripen in its presence.

The second banana which was placed with a ripened apple became yellow and soft because it got ripened in presence of apple. This happened because of secretion of 'Ethylene' by the apple. Ethylene is a gaseous hormone and promotes fruit ripening. It is secreted by all parts of seed plants. As the Ethylene was secreted by the apple, the banana which was placed with apple got ripened under the influence of Ethylene.

Hence the student might reach the conclusion that the apple emitted a substance (the gaseous hormone ethylene) that caused the banana to ripen in its presence.

So, the correct answer is 'The apple emitted a substance that caused the banana to ripen in its presence'.