Because we can't take in light energy directly, we consume plants. Plants convert light energy into chemical energy through the process of photosynthesis. So when we eat plants, we get the chemical energy stored in the carbohydrates, which fuels all our physical activity.
Through a sequence of steps called the immune response<span>, the </span>immune system<span>attacks these </span>pathogens<span>. ... This is the </span>immune system<span>. Cells. The cells involved are white blood cells (leukocytes), which seek out and destroy disease-causing organisms or substances</span>
