Algae as a Possible Way to Remediate the Problem With a Plant-Based Diet

The emphasis in your world is on algae as being the possible way to remediate this problem with a plant-based diet. Algae are very simple plants. Most of them live in water, and they take up vitamin B12 from the liquid that they live in. So bacteria that are also living in the same place, like in a pond or a river or even the sea, the bacteria make the B12, and then algae take it up. And the algae conveniently package it for us, and if the algae would get the B12. Whereas plants don't do that.