Which part of the alimentary canal of poultry is responsible for the grinding of food?

Step 1: 1.1 Enzyme in human saliva that hydrolyzes starch. Salivary amylase (also known as ptyalin) breaks down starch into maltose in the mouth. Rennet curdles milk, pepsin digests proteins in stomach. Answer: A A Step 2: 1.2 Enzyme in the wall of calf stomach for fermentation/curdling of milk to yogurt. Rennet (chymosin or rennin) from calf stomach lining coagulates milk proteins for yogurt and cheese production. Answer: B B Step 3: 1.3 Enzyme that digests proteins (pepsin) and rennin in stomach HCl for milk curdling. Pepsin digests proteins into peptides in acidic stomach; rennin (rennet) curdles milk (both active in stomach). Combination of functions described matches C. Answer: C C Step 4: 1.4 Process that mixes/pushes food through small intestine walls (emulsification, regurgitation, etc.). Peristalsis (wave-like contractions) and segmentation (mixing) move and mix food for absorption through small intestine walls. Answer: C C Step 5: 1.5 Part of elementary canal of poultry responsible for function (rumination/storage/grinding). Poultry have no rumen/rumination (ruminants do); crop stores/moistens food, proventriculus secretes acid/pepsin, gizzard grinds food mechanically. Matches described roles. Crop (storage): B Gizzard (grinding): C Proventriculus (digestion): D B, C, D Step 6: 1.6 Processes in elementary canal of farm animals for nutrient absorption. Diffusion (passive, e.g., lipids), but most nutrients (glucose, amino acids) use active absorption against gradient in small intestine. Answer: D D