Why do scientists think Earth's core contains iron?

Which statement is a proper biconditional statement for the conditional statement: if a line intersects a line segment at its midpoint, then it is a segment bisector. if a line is a segment bisector, then it intersects the line segment at its midpoint. if a line does not intersect a line segment at its midpoint, then it is not a segment bisector. a line intersects a line segment at its midpoint if, and only if, it is a segment bisector. if a line is not a segment bisector, then it does not intersect the line segment at its midpoint.

The solstices and equinoxes, and the number of hours of daylight associated with each, are major factors in the seasons. use the drop-down menus to identify the month when each of these events occurs. the winter solstice in the northern hemisphere: an equinox in both hemispheres: the summer solstice in the northern hemisphere:

What must happen for new french words to be published in official dictionaries? a. they must be approved by the french academy b. they must be voted on by the people of france c. they must be used by famous french writers d. they must be used by philosophers a. they must be approved by the french academy