Krishna begins answering. That which never perishes — that is the supreme Brahman. The essential nature of every being — the soul — is called adhyatma. And the creative activity that brings beings into existence is called karma.
Consider a seed. The seed itself never truly changes — plant it, and it produces the same kind of tree, season after season. That unchanging essence is like Brahman. The tree's own character — giving shade, bearing sweet fruit — that is its svabhava, its nature, like the soul within each of us. And the sprouting of the seed into a sapling — that creative unfolding — that is karma.
Krishna distills vast concepts into clear, graspable definitions. Each word carries the weight of the Upanishads, yet the explanation flows as simply as an elder explaining life's biggest truths to a grandchild.