Which of the following is an example of a simple machine?


What is the primary function of the nervous system?


Which gas is produced during photosynthesis?


What is the main purpose of the skeletal system?


Which of the following is a characteristic of acids?


What is the primary source of energy for photosynthesis?


Which of the following is a function of the liver?


What is the main component of the Earth's crust?


Which type of electromagnetic radiation has the longest wavelength?


What is the primary purpose of the digestive system?