Father & son mail chat

Dear Dad,
$chool i$ really $well. I am making lot$ of friend$ and $tudying very hard. I have $o much $tuff, i $imply can't think of anything i need. $o, if you like, $end me a card, a$ i would love to hear from you.
Love your $on.

Dear Son,
I kNOw astroNOmy, ecoNOmics, and oceaNOgraphy are eNOugh to keep an hoNOrs student busy. Do NOt forget that the pursuit of kNOwledge is a NOble task, and you can't study eNOugh.
Love, Dad.