The question is: My purpose is to learn Torah- what will help me do that? Basic addition (for me personally), yes. American History, no. Chemistry, no. Zoology, biology, maybe. English Grammar, no
You need to Know Zoology to know about Kosher Animals especially Fish (Zoology and Biology are related)
A few years ago some Bochrim could not burn Chometz on Eruv Peseach because it was too windy and tried to use Paint Thinner (and disatrous results), that is Chemistry
Many Jews (Probably a Majority) Speak English and if you want to properly relate torah to them Proper English and English grammar is expected. Many Seforim are written in english and many people expect good quality english writing from these books