Question

three centuries ago, issac newton wrote: “... to myself i seem to have been only like a boy playing on the seashore... whilst the great ocean of truth lay all undiscovered before me.” when newton surveyed the vast ocean of truth which lay before him, the laws of nature were shrouded in an impenetrable veil
but the ocean that newton knew as a boy has largely disappeared. before us lies a new ocean, the ocean of endless scientific possibilities and applications, giving us the potential for the first time to manipulate and
how does ocean build as a key term between the two passages?
ocean metaphorically represented scientific unknowns but now represents possibilities.
ocean metaphorically represents where science was and where it is going in the future.
ocean metaphorically represents the unknown to newton but the known to kaku.

Explanation:

In the first passage, Newton's "ocean of truth" was an unknown (laws of nature were undiscovered). In the second passage, the "new ocean" is of scientific possibilities (manipulation and molding of nature's forces). So, it changed from representing unknowns (to Newton) to possibilities.

Answer:

Ocean metaphorically represented scientific unknowns but now represents possibilities.