The color of a star is primarily determined by its blue is the hottest color, our sun is cooler yellow

The largest internal organ in the frog is the

Simple astronomical telescope the objective lens has a focal length of 75 cm and that of a piece of 5cm of the lenses are 18 cm apart when will be final image of a distant object before

Compared with the land in the highlands, the lowlands region of england a) rockier and more difficult for farmingb) the center of business and industryc)richer in coal reservesd)covered by more fertile farmland d) covered by more fertile farmland