How was insulin obtained before the advent of rDNA technology? What were the problems encountered?

Explanation

**Step-by-Step Solution:**

1. **Understanding Insulin and its Function**:
- Insulin is a hormone produced by the pancreas that regulates blood sugar levels in the body. It is crucial for maintaining glucose homeostasis.

2. **Source of Insulin Before rDNA Technology**:
- Before recombinant DNA (rDNA) technology was developed, insulin was extracted from the pancreases of slaughtered animals, primarily cattle (cows) and pigs.

...