No 2 people in the world are "exactly alike", so the odds would be 0% chance. Twins, might be closer in alike-ness, but they still aren't "exactly alike". Hope this answered your question.
Its called osmosis and it only happens with water. now I'm just adding words to be able to post this. its moving down the concentration gradient.
Answer:
The correct answer would be the slide should be almost in focus when changing to higher magnifications.
A parfocal lens is a type of lens which stays in focus when focal length or magnification is changed.
Parfocal microscopes are those in which objectives remain in focus even when magnification is changed for example, when it is switched from 10x to 40x, the object or slide remains at the focus.