Motility and secretion in the stomach is generated by the reflex initiated by thought, smell, sight, or taste of food.

Explanation:

The cephalic phase reflex of gastric secretion, which is relatively brief, takes place before food enters the stomach

The smell, taste, sight, or thought of food triggers this type of reflex

For example, when we bring a piece of food item to our lips, impulses from receptors in our taste buds or the nose are relayed to our brain, which returns signals that increase gastric secretion to prepare our stomach for digestion

This enhanced secretion is a conditioned reflex, which means it occurs only if we like or want a particular food

Depression and loss of appetite are two factors which can suppress the cephalic reflex

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.