Tutor profile: Kelly H.
Subject: Earth Science
Despite the fact that the Earth's inner core is 5,000 ºC, it is solid. How is this possible?
The inner core is made of very dense, heavy materials including iron and nickel. Though they should melt, the immense pressure at the inner core allows for them to be solid, despite the temperature that's well above their melting point.
Widow's peak is a dominant trait that follows a pattern of simple Mendelian inheritance. If a heterozygous parent has a child with a homozygous recessive parent, what is the likelihood that their offspring will be born with a widow's peak?
The likelihood is 50%, or 2 out of 4. If you set up a Punnett square, with the heterozygous parent Ww on one side and the homozygous recessive parent on the other, and cross the two. The offspring produced should be Ww, Ww, ww, and ww. In the case of simple dominance, heterozygous individuals will express the trait. In other words, the Ww individuals will have widow's peaks. The homozygous dominant offspring (ww) will display the recessive form, in this case no widow's peak, or a straight hairline.
What is the advantage to the four-chambered structure of the mammalian heart?
Separation into a pulmonic and systemic circuit produces maximum efficiency. Separate circuits ensure there is now mixing of blood that is low in oxygen with blood that is oxygen rich. This results in the most carbon dioxide being removed from the body's tissues and oxygen delivered to these tissues.
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