Your body gets the things it needs to survive by your brain telling you that its either hungry or thirsty so you can stay energized your body also tells it self when to go to sleep which is something we all need
The correct answer is "neurons".
Neurons are nerve cells which connect to each other using synapses and form neural networks. They exhibit high levels of specialization and are the primary components of the central nervous system.
Myofibrils are contractile fibers which form the striated muscle cells. Sarcomeres are the structural unit of the myofibrils.
Answer is Biogeochemical cycles.
In an ecosystem biotic (living) abiotic (non-living) components constantly interact each other. During these interactions, there is a transfer of nutrients between living organisms and the non-living environment. Thus, there is recycling of inorganic matter between living organisms and their non-living environment. This cycling of matter is called biogeochemical cycles.
Shells are the exoskeletons of clams, snails and oysters. Hope that helps