A, the endosymbiotic theory tells us that a looooong time ago, when there were only one-cell organisms, they kind of took in a bacteria. They profited from having a bacteria in it ( and I believe it is believed that this made it possible for organisms to have multiple cells, not sure) and these bacteria became mitonchondria/chloroplasts, thus answer A is the only one that doesn't support this theory.
TCGACTGGATCGCCTGTT
DNA has T instead of U :)
The expression or comment "Brain Freeze" means that the roof of your mouth is getting so cold that its affecting some of the nerves in your brain making it feel like a brain freeze.
Olfaction is not a tactile sensation, nor it's related to chewing food.
Olfactory receptors are chemical receptors in the nasal cavity that react with different odors creating the sense of smell that is interpreted in the brain.
So, olfaction is a chemical sensation that we experience while inhaling different odors through our noses.