Answer:
The correct answer is: geography and UV radiation.
Explanation:
Skin variation occurred thanks to evolution, and was driven as a consequence of the geographical location of different populations of humans.
The humans that lived in hot and sunny places, closer to the equator, where much more exposed to the sun's ultraviolet radiation. In order to survive the amount of UV lights that they were exposed to, new humans in those regions were being born with a darker skin tone, which was rich in melanin (a brown pigment that protects us from the sun radiation).
Contrary to these humans that lived in the tropical areas, the humans that populated the areas that were closer to the poles, developed much lighter skin as a result of lower amounts of melanin in their skin. Since sun exposure in the poles is very limited, humans needed to receive as much as they could for the production of Vitamin D, and thus, their skins got lighter and less protected.
Answer:
b
Explanation:
state agencies
(that's my opinion on this question)
Answer: Gray whales have no dorsal (back) fins. Instead, they have a low hump and a series of six to twelve knuckles or bumps. Gray whales are baleen whales, and each has approximately 300 plates of cream-colored baleen hanging from its upper jaw. Two to five throat creases allow their throats to expand during feeding.
Explanation:
<u>Answer</u>:
In an ideal intercuspal position, the mesiofacial groove of a mandibular first molar opposes "A triangular ridge of the mesiofacial cusp" of the maxillary first molar
<u>Explanation</u>:
Triangular ridges are those which arises from the cusp guidelines of premolar and molars near the central groove. Transverse ridges are designed by the grouping of two triangular ridges on the posterior teeth. The connection of the buccal and lingual triangular ridges is frequently termed as an example. Being a non-functional cusp it is a mandibular tooth. The crown touches into lingually. The cusp has four cusp edges they are mesiobuccal, distobuccal, mesiolingual and distolingual. The buccal and lingual triangular edges will lead to the establishment of the transverse edge in the central groove part.