The video shows a 5 kingdom and 6 kingdom system.
Why is classification subject to change?

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation:

if you look up in the top right corner you'll see your current profile picture, click than click "view profile" you'll be able to change it there.