Answer:
<span>D. It responds when pathogens enter the body.</span>
Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself.
1 kilometer. 1 km is 100,000 cm
this ones simple all the others don't use sunlight because they cant make food within themselves but plants on the other hand use direct sunlight to make their food unlike the others. ;]
