Why distances of only nearby stars can be found only by parallax method ?

The principle of 'parallax' is used in the determination of distance of nearby stars. The role of distant object O there is now taken by nearby distant stars. The baseline AB is the line joining the Earth's two locations six months apart in its orbit around the Sun. That is the baseline is about the disameter of the earth's orbit = 3 xx 10^11 m. However, even the nearest stars are so distant that with such a long baseline theyshow parallax only of the order 1 s of arc or so. A parsec is a convenient unit of length on the astronomical sxale. It is the distance of an object that will show a parallar of 1s of arc from opposite ends of a baseline equal to the distance from the Earth to the Sum How much is a parsec in terms of metre?

If A is any m xx n matrix, then A^2 can be found only when

Explain why choroplasts are found only in plant cells?

A diminihsed virtual image can be produced only with