Give scientific reasons: In earlier times,insulin was extracted from the pancreas of slaughtered cattle.

(N/A) Insulin is a hormone produced by the $\beta$-cells of the pancreas that regulates blood glucose levels. In the human body,it is produced in limited quantities. Before the advent of modern biotechnology,there was no method to synthesize human insulin in large quantities. Therefore,to treat patients suffering from diabetes,insulin was extracted from the pancreas of slaughtered cattle and pigs. However,this insulin often caused allergic reactions in some patients because it was not identical to human insulin.