The Sea Slug, Elysia Chorotica, Has No Nematocysts or Dinoflagellates

Multiple Choice

The sea slug, Elysia chorotica, has no nematocysts or dinoflagellates but, rather, has "naked" chloroplasts in its skin. The chloroplasts are all that remain of the seaweed (Vaucheria sp.) that Elysia feeds upon. The chloroplasts are transferred to the skin; consequently, this slug is green. It spends most of its time basking in shallow water on the surface of seaweeds. How should we expect its chloroplasts to benefit the Elysia sea slug?
1) provide Elysia with fixed CO₂
2) provide Elysia with fixed N₂
3) provide Elysia with protective coloration

A) 1 only
B) 2 only
C) 3 only
D) 1 and 3
E) 1, 2, and 3