1. What are two natural processes in which ammonia is created? a.) denitrification and ammonification
b.) nitrification and denitrification
c.) nitrogen fixation and nitrification
d.) nitrogen fixation and ammonification

it creates acid rain

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.