What are some examples of connections of photosynthesis to the real world other than it producing oxygen?

Types of scientific inquiry that biologist engage in that cannot be completely controlled

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

Which of the following sentences has a compound predicate?