Question

everyone ____________needs to exercise regularly
..................pls say the reason and it belongs to sub jet verb agreement

Answer 1

here also it is given that everyone should do it
it shows the daily action. we can say that its a daily action because there is  given a word 'regularly'. so its a daily action
hence the verb will be added with 's'

Answer 2

Everyone is a singular noun. Hence instead of need; 'needs' is used.

Everyone,Anyone,No one are all such singular nouns.