Animals perceive conditions and changes in their environment via stimuli detected by ____.

A) sensory receptors
B) nerve pathways from the brain to the sensory receptor
C) thermoreceptors in the brain
D) sensory adaptations
E) action potentials of varying size

Sensory receptors are specialized structures that detect various stimuli in the environment and transmit signals to the nervous system. Nerve pathways, sensory adaptations, and action potentials are all involved in the processing and transmission of sensory information, but they are not the primary means by which animals detect environmental stimuli. Thermoreceptors in the brain specifically detect temperature changes within the body, rather than external stimuli.