When you feel cold, there are sensors in your skin that tell the brain you need to warm up. The brain sends messages, by way of nerves, to the muscles in your body causing them to contract and relax very quickly resulting in a shiver. The movement of the muscles during a shiver generates heat which can be used to warm up the surrounding tissues. Which characteristic(s) of life is being represented during this action? A) respond to stimuli
B) maintain homeostasis
C) growth and adaptation
D) respond to stimuli and maintain homeostasis

I think the answer is respond to stimuli and maintain homeostasis

mammal

explanation:

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.