What is the significance of 'am' in german?
Would "Es ist learnt." be considered correct?
No. German doesn't have a continuous aspect. Both "It is learning" and "It learns" translate as "Es lernt".
lernt = is learning/learns
It doesn't need an extra "is".
why not (Das lernt? )??
Das is an article, not a pronoun. "The learns" or "the is learning" doesn't make any sense.
"das" can also be a demonstrative pronoun, but in this case, "es" sounds more natural.