Option b is correct..
Caves are formed by the dissolution of limestone. Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.
building block for the new double helix strand.
Answer:It works by relaxing the muscles of the airways into the lungs, which makes it easier to breathe. Salbutamol comes in an inhaler (puffer). Salbutamol inhalers are usually blue. Salbutamol is sometimes given as tablets, capsules or syrup for people who cannot use an inhaler very well.
Explanation:
C because oxygen was a byproduct of photosynthesis and proved to be EXTREMELY important in the atmosphere.