Final answer:
In the evolution from percursaria, Gayralia, to ulva, there has been a loss of multicellularity and acquisition of chloroplasts.
Step-by-step explanation:
In the evolution from percursaria, Gayralia, to ulva, several changes have occurred. Firstly, there has been a loss of multicellularity. Percursaria and Gayralia are multicellular, while ulva is considered to be true multicellular. Additionally, ulva has undergone an acquisition of chloroplasts. Chloroplasts are responsible for photosynthesis, and their presence in ulva allows it to produce food through this process. Therefore, the correct answer is D) Acquisition of chloroplasts.