rDNA is using genetic cloning to form DNA molecules from different species. in this example you can make the hormone insulin by getting some of the components from one organism and getting the remainder from another organism. Specifically, Insulin has 2 amine chains, so you can get 1 amine chain from one organism, and the other from a different one. Then you can combine them and you'll get insulin.
The answer is; D
Solar cells usually convert solar energy into electricity which could later be reserved. The efficiency of solar cells is still low, compared to other sources, with a conversion rate of 15% - 22%. This reduces the attractiveness of solar cells as a competitive source of energy. This also makes this form of energy expensive due to its inefficiency.