Responses to the Environment

What is an example of positive taxis in insects?

• Staying stationary in light

• Moving towards light

• Moving away from light

• Random movement in response to light

What triggers the migration of some bird species?

• Changes in temperature

• Availability of water

• Changes in daylight hours

• Predator presence

What does the presence of light trigger in human circadian rhythms?

• Increase in cortisol

• All of the above

• Suppression of gene expression

• Decrease in melatonin

What is the role of auxin in plant growth?

• It decreases growth towards light

• It increases growth away from light

• It promotes growth towards light

• It has no effect on growth direction

What is the significance of uninterrupted darkness for short day plants?

• It signals time to hibernate

• It triggers flowering

• It causes leaves to fall

• It has no significant effect