Stimulus is something that causes a psychological response. It can be internal or external. The stimulus is the contact with the hot pan. It is an external stimulus. Sense organs, such as the sensory receptors in the skin are sensitive to external stimulus. The quickly pull of your hand is a reflex action.
The contact causes a nerve impulse that will travel to the spinal cord via the sensory neurons.<span>To respond to the stimulus of the reflex arc, the muscle needs to contract to pull the hand quickly away from the hot pan.</span>
Carbon cycle is process that shows the exchnge of carbon in the living and atmospheric system. Carbon cycle starts with the giving off of carbon dioxide from nimals, accumulation of co2 of plants, contribution of organic matter of dead animals and plants, photosynthesis, etc. The answer is D. fermentation
What is waste water treatment ?
“The major aim of wastewater treatment is to remove as much of the suspended solids as possible before the remaining water, called effluent, is discharged back to the environment.”
My source is from www.usgs.gov
