Analogous Organs : Analogous organs are organs, that have similar look and/or functions in different organisms, but do not share a common evolutionary origin.

For example,
* wings of insects vs. wings of bird.
* In some plants, stems, may look and function like leaves...but they have different origins!

Vestigial Organs : Vestigial organs are group of organs with no particular use now but may have been useful in ancestors.
For example tailbone coccyx or hip bones in whales.

Sex chromosome : Sex chromosomes are the 23rd pair of chromosomes that determine the sex of an individual.
X Chromosome - Female (XX) and
Y Chromosome - Male (XY).
Half of total chromosomes come from father, half come from mother.