Which change is an example of a response to a stimulus? 1.
The pupil of an eye decreases in size in bright light.
2.
A leaf absorbs sunlight in the morning.
3.
The water level of a pond rises on a rainy day.
4.
A dead tree decays after many years.
S

1

Explanation:

i think its white blood cells

i hope this

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.