Circulatory system and nucleus
D. sum of all chemical reactions in an organism
Answer:
Neurons have stable, relatively unchanging internal environments.
Explanation:
Neurons or nerve cells is the structural and functional unit of the nervous system. Neurons consists of the dendrites, axon, cell body and different cell organelles.
The neurons have mitochondria that meets the high ATP requirement and and consume more oxygen. The network of rough endoplasmic reticulum and ribosomes produce large number of proteins in neuron. The internal environment is never stable and gets changed as the nerve impulse transmission occur through the neuron. The membrane potential of the neuron gets changed and changes its internal environment.
Thus, the correct answer is option (B).
Answer:
Amino acids
Explanation:
Nitrogen is a major part of amino acids. Which are the building blocks of proteins and nucleic acids.