Why might it be beneficial for plants to exhibit phototaxis

You have learned that photosynthesis always brings new food to the earth. There is another reason why photosynthesis is so important. Oxygen is produced during photosynthesis. Humans and animals need oxygen to stay alive. Plants themselves also need oxygen. Through the photosynthesis, new oxygen is constantly coming into the air. Without photosynthesis, the oxygen in the air would slowly run out. All living beings would then die. In many plants, photosynthesis does not only occur in the leaves. Photosynthesis can take place in all green parts of a plant. For plants with green stems, photosynthesis also takes place in the stems. But most photosynthesis takes place in the leaves. The leaves therefore have the special function of allowing photosynthesis to take place.

Explanation:

≅200-130 milions years ago pangea splited in 2 continents

i believe it would be the lungs.