Question

_____ waves are electromagnetic waves just below red in the visible spectrum, so our eyes cannot see them. most remote controls for objects like led lights, televisions, and streaming devices work using infrared light.
○ gamma rays
○ radio waves
○ ultraviolet
○ infrared

question 21
1 pts
which of the following statements most accurately describes the effect of caffeine and the other stimulants on the nervous system?
○ they decrease central nervous system activity
○ they decrease somatic nervous system activity
○ they increase sympathetic nervous system activity
○ they decrease sympathetic nervous system activity

question 22
1 pts
psychoactive drugs achieve their effects by
○ blocking the action of neurotransmitters
○ mimicking neurotransmitters
○ any of these
○ blocking the reuptake of neurotransmitters

Explanation:

Question (First Question about Waves)

To solve this, we recall the electromagnetic spectrum. Infrared waves are just below red in the visible spectrum (in terms of wavelength/frequency), and remote controls use infrared. Gamma rays have high energy, radio waves are low - energy and long - wavelength, and ultraviolet is above violet. So the correct option is Infrared.

Stimulants like caffeine increase the activity of the nervous system. The sympathetic nervous system is part of the autonomic nervous system and is involved in the "fight - or - flight" response. Stimulants increase sympathetic nervous system activity. The other options are incorrect: they don't decrease central or somatic or sympathetic nervous system activity.

Psychoactive drugs can act in multiple ways: they can block neurotransmitter action, mimic neurotransmitters, or block reuptake. So "any of these" is correct as different psychoactive drugs use different mechanisms from this set.

Answer:

Infrared (the option labeled "Infrared")

Question 21 (Effect of Caffeine and Stimulants on Nervous System)