<span>180 degrees, 120 degrees.
The Carbon are all in a straight chain, with the Hydrogen at angles at the end.
From VSEPR theory, the Carbons bond in an AX2 system, and the H C H bond is an AX3 system, which provide the two different angles.</span>
<span>Basal Body Temperature (BBT) is the body temperature upon waking up
or when a person is at rest. After ovulation, a woman’s BBT rises because of increase in
progesterone level. BBT swill stay high throughout the post-ovulation phase and
until the following cycle. If there is pregnancy, BBT will stay high.</span>
Half-life is<span> the term for the amount of time it takes 50% of an element to decay</span>
Some isotopes, however, decay slowly, and several of these are used as geologic clocks. Dating rocks by these radioactive timekeepers is simple in theory, but the laboratory procedures are complex. <span>All methods rely on the fact that certain elements (particularly uranium and potassium) contain a number of different isotopes whose half-life is exactly known and therefore the relative concentrations of these isotopes within a rock or mineral can measure the age.</span>
