Question

genetic engineering has produced goats whose milk contains proteins that can be used as medicines. this effect was produced by: a inserting foreign genes into fertilized goat eggs b injecting foreign genes into the goats udders c genetically modifying the nutritional needs of the goats offspring d mixing foreign genes into the milk

Explanation:

Genetic engineering involves manipulating an organism's DNA. To produce goats with milk containing medicinal proteins, foreign genes (encoding the desired proteins) need to be inserted at an early stage. Inserting foreign genes into fertilized goat eggs allows the gene to be present in all cells of the developing goat (including mammary gland cells which produce milk). Injecting genes into udders (B) would not ensure the gene is passed on or expressed consistently. Modifying nutritional needs (C) doesn't directly introduce the gene for the medicinal protein. Mixing genes into milk (D) is not a valid genetic engineering method as genes need to be integrated into the organism's genome.

Answer:

A. inserting foreign genes into fertilized goat eggs