B- yeast is used for baking things, it helps the dough rise in bread and pizzas etc
"They contain at least one double or triple bond" is true of saturated fatty acid chains. This extra bond is why they are called "saturated", because they had less ability to take on other bonds.
IL-2 is one of many cytokines that govern the immune response. It acts as a mitogen for T cells, potentially enhancing their proliferation and activity, improving antigen generation, and raising the synthesis and release of other cytokines.
1.B
2.B
I mean that's what you teachers probably think the answer is but only a very hopeless and sad person should think evolution exist, if it did, why isn't happening today, or why don't we see changes.
Extinction of losing its species hope this helps you