B) spatial significance what evidence of a
large glacial lake is there in northeastern
ontario?

Evidence of a  large glacial lake northeastern  Ontario:

The evidences of a large glacial lake in northeastern Ontario are, sand ridges of Rome, relief forms in the plain around the lake in Ontario, the structure of the soil and the glacial remains.

This large glacial lake was named Iroquois which existed approximately 13000 years ago and is said to be enlargement of today's Ontario lake. This was formed because the St Lawrence river was blocked by an ice sheet and it drained towards the south east.