The correct answer is option d, that is, neurotransmitters.
A neurotransmitter refers to a chemical component, which is discharged at the terminal of a nerve fiber by the introduction of a nerve impulse, and by diffusing across the junction or synapse. It helps in the transfer of the impulse to another muscle fiber, nerve fiber, or some other composition. Acetylcholine is a kind of neurotransmitter, that is, used by neurons in the CNS and the PNS in the control of activities ranging from heart rate and muscle contraction to digestion and memory.
A contractile vacuole works just the same as the name suggests, in that it expands and contracts. The point of the contractile vacuole is to pump water out of the cell through a process called osmoregulation, the regulation of osmotic pressure. It occurs in freshwater protists, but mainly in the kingdom Protista as a whole.
this ones simple all the others don't use sunlight because they cant make food within themselves but plants on the other hand use direct sunlight to make their food unlike the others. ;]
B.
Asbestos was used in housing for many years because it was cheap to manufacture and was amazingly heat-resistant, but was found to be incredibly dangerous, causing innumerous accounts of lung cancer and related problems.
This is from memory, but I will double check after I answer.
Answer:
Red blood cells (RBC)
