Add punctuation: He clearly saw however the full force of the principle of natural selection
A: He clearly saw, however, the full force of the principle of natural selection.

Add punctuation: Yes You can convert many different file types into Google Slides format The original file will remain intact
A: Yes. You can convert many different file types into Google Slides format. The original file will remain intact.

Add punctuation: 3 Write down command on the needed button just hold mouse pointer within button rectangle
A:
3 - Write down command on the needed button (just hold mouse pointer within button rectangle).