<span>The answer is to control the crossing of the traits.
The idea of preventing plants from self-pollinating is to control the crossing of the traits. If plants were self-pollinating, he could not know if the traits are inherited from the same plant or from the other. By preventing this, he could cross parents with known phenotype and that way learn about crossing process and inheriting process.</span>
Vitamin b12 is the most popular deficiency at the moment- B12 creates red blood cells which travels oxygen around the body- having B12 deficiency can lead to anaemia.