Scoville units is the scale used to determine how "hot" a pepper is.
A sweet bell pepper, which isn't spicy at all, has a ranking of 0.
The Carolina Reaper, one of the hottest peppers in the world, has a ranking of up to 2,200,000.
The 4th option, eye color is not an inherited trait
1. Cranial roof & cranial base
2. Frontal bone, parietal bone, temporal bones, occipital bone, sphenoid bone, ethmoid bone
3. Inferior tribunal (2), lacrimal bones (2), mandibal, maxilla(2), nasal bones (2), palatine bones (2), vomer, zygomatic bones (2)
Due to being able to develop immune enzymes or toxins to fight and survive