Assertion: In cocklebur [Xanthium strumarium], interruption of the light portion of the photoperiod by a brief exposure of darkness inhibits flowering.
Reason: The cocklebur plant is responsive to day length for induction of flowering.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion: Unlike plants like mangroves, plants less specialized to cope with oxygen deprivation in water logged soils, respond by producing ethylene.
Reason: Ethylene promotes cynaobacterial growth in the surrounding water that increases its oxygen content.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false

Assertion: Commercial onion growers store sets at low temperature, but devernalize them before planting.
Reason: It is possible to devernalize a plant by exposure to sometimes low or high temperatures subsequent to vernalization.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false

Like animal hormones, plant hormones:
1. are transported by a circulatory system
2. do not act locally
3. are steroids
4. activate signal transduction pathway

What is incorrect regarding the results of experiments conducted on coleoptiles of canary grass and oats by Charles Darwin and Francis Darwin on phototropism?
1. Both plants grow toward the light source.
2. The tips of coleoptiles were covered with a metal foil and the coleoptiles did not grow toward light.
3. When the metal foil was removed they still not grew toward the light.
4. The growing region of the coleoptiles rather than their tips was covered and the coleoptiles grew toward the light.

In 1913, Peter Boysen-Jensen further developed on the Darwins experiments. Identify the statement that does not relate to his experiments:
1. He cut off the tip of a coleoptile and noticed that it stopped its growth
2. He then separated the tip from the coleoptile with a tiny piece of agar and observed that the coleoptiles grew and curved toward the light.
3. He replaced the agar block with butter and observed that the coleoptiles grew and curved toward the light.
4. He replaced the agar blocks with pieces of Ptatinum foil, and there was no growth.

F. W. Went cut off the tips and placed the cut surfaces onto agar. The tips were removed after an hour and the agar was placed on the cut tips of the coleoptiles grown in the dark. His different experiments and results did not include:
1. Cut off coleoptiles and without agar blocks, did not grow.
2. Agar blocks that contacted cut tips were placed on the center of the cut off coleoptiles and they grew straight up.
3. Agar blocks that did not contact the cut tips of coleoptiles did not show any response.
4. Agar blocks that had contacted the cut tips when placed on one side of the cut off coleoptiles, curved towards the agar blocks.

Generally, plant hormones do not control plant development by affecting:
1. the majorly citric acid cycle and the anabolic Calvin cycle
2. cell division via the cell cycle
3. cell elongation through acid growth
4. mediating short-term physiological responses to environmental stimuli

The practical uses of auxins include:
I. Use of IBA in vegetative propagation of plants by cutting
II. As a herbicide for eliminating eudicot broad-leaf weeds
III. Making greenhouse cultivated tomatoes more viable commercially

Plants bend toward light because
1. light is the source of energy that drives photosynthesis.
2. the sun stimulates stem growth.
3. cell expansion is greater on the dark side of the stem.
4. there is inactivation of auxin on the dark side of the stem.