TRANSDUCTION. This refers to the stimulus being converted into an action potential which is then transmitted in the axons going to the central nervous system. This usually starts at the receptor cell. The stimulus change the electrical potential across the cell membrane. This will result in depolarization of the membrane which allow the action potential to be transmitted towards the brain where the electrical impulse is integrated. This usually happens in sensory cells in the body such as vestibular apparatus, olfactory cells, the retina and even the nerve endings alls over our body.
The hole is a separate phenomenon because it correlates something other than global warming. it doesn’t focus on global warming but more on specific areas.