5.11

• Farmers collect the milk but leaves part of it to breed more cows.
• A few cows would produce 50 ml but other can produce 150 ml but the average for a cow is 100 ml.
• Cows produce high yield so the breeding population can become selective.
• The next generation of cows will produce more milk.
• The milk yield would be genetic which means that the farmer will select one with good characteristics to breed.