Questions

When modifiers are misplaced or put in the wrong place, things can get quite confusing. A modifier adds detail or limits or changes the meaning of another word or phrase. 

Here Option A) "Covered in fluffiness, the couple played with the kitten" is the ony sentence contains a misplaced modifier. In the sentence, it gives the meaning that the couple are fluffy not the kitten.

2020 summer Olymic games to be held in Tokyo, Japan.

The centripetal force having been removed the body cannot  execute the curved path

Eugenics is the study of altering human beings by changing their genetic components.

It is the study of the agencies under social control that may improve or impair the racial qualities of future generations either physically or mentally.