Question

which organisms have not been genetically engineered to produce spider silk? insects yeast cows plants bacteria

Explanation:

Bacteria, yeast, plants, and insects have been genetically engineered to produce spider silk proteins in research or commercial contexts. Cows are not typically used for this purpose; common engineered organisms for spider silk focus on microbial, fungal, plant, or insect systems for scalable production.

Answer:

cows