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

Ex Input:
Passage: The jointed appendages of arthropods may be used as legs for walking. Being jointed makes them more flexible. Try walking or climbing stairs without bending your knees, and you'll see why joints are helpful. In most arthropods, the appendages on the head have been modified for other functions. Figure below shows some of the head appendages found in arthropods. Sensory organs such as eyes are also found on the head. Answer: walking

Ex Output:
What may the jointed appendages of arthropods be used for?

Ex Input:
Passage: Dissolved mineral salts wash into the ocean. As ocean water evaporates, it leaves the salts behind. This makes the water saltier. Ocean water is about 3.5 percent salts. The main salt is sodium chloride. Answer: salts

Ex Output:
Concentration of what, the substance left behind when ocean water evaporates, is about 3.5 percent?

Ex Input:
Passage: The bonfire from the opening image has a lot of thermal energy. Thermal energy is the total kinetic energy of moving particles of matter, and the transfer of thermal energy is called heat. Thermal energy from the bonfire is transferred to the hands by thermal radiation. Thermal radiation is the transfer of thermal energy by waves that can travel through air or even through empty space, as shown in the Figure below . When the waves of thermal energy reach objects, they transfer the energy to the objects, causing them to warm up. This is how the fire warms the hands of someone sitting near the bonfire. This is also how the sun's energy reaches Earth and heats its surface. Without the energy radiated from the sun, Earth would be too cold to support life as we know it. Answer: thermal radiation from the sun

Ex Output:
How does heat travel from the sun to the earth?