Given a scientific passage and an answer, generate a question for the given answer.

Input: Consider Input: Passage: Connective tissue consists of cells that form the body's structure. Examples include bone and cartilage, which protect and support the body. Blood is also a connective tissue. It circulates and connects cells throughout the body. Answer: connective

Output: What tissue consists of cells that form the body's structure?

Input: Consider Input: Passage: The Sun gives off energy in tiny packets called photons . Photons travel in waves. Figure below models a wave of light. Notice the wavelength in the figure. Waves with shorter wavelengths have more energy. Answer: photons

Output: What are the tiny packets of energy the sun gives off called?

Input: Consider Input: Passage: You may think that your blood vessels have thick walls without any leaks, but that's not true. Blood vessels can leak just like any other pipe. The lymphatic system makes sure leaked blood returns back to the bloodstream. Answer: lymphatic
Output: What system makes sure leaked blood returns back to the bloodstream?