Which of the following is a common by-product of farm animals?

Explanation

Farm animals provide multiple products. Milk is a primary dairy product. Wool comes from sheep. Manure serves as organic fertilizer. All three are common farm animal products.

Other by-products include: hides and skins (leather), bones (gelatin, fertilizer), feathers (bedding, decoration), and blood (animal feed, fertilizer).

By-products add value to livestock farming beyond meat production. Nothing is wasted – even waste products like manure become valuable farm inputs.