Biological hazards are substances that pose a threat to living things.
~ThePirc
It gets blurry and further away because it is not changing
The situation is an example of negative reinforcement.
In the condition of negative reinforcement, a stimulus especially an unpleasant stimulus is removed due to a particular behavior of the person. In this case, the unpleasant behavior is the headache, and taking aspirin is a behavior of Nancy, which cut of the stimuli, that is pain relieving. In negative reinforcement a particular behavior is increased, in order to remove the unpleasant stimulus.
I think Subarctic, Ice cap and Tundra.
Hope it helps :)
El hielo flota porque es menos denso que el agua líquida. Cuando se forma hielo, ocupa aproximadamente un 9% más de espacio del que ocupaba como líquido. Por lo tanto, un recipiente de 1 litro de hielo pesa menos que un recipiente de 1 litro de agua líquida y el material más liviano flota hacia
