Chọn từ phù hợp nhất để điền vào chỗ trống trong đoạn văn sau:

Plants supply man with food clothing, and shelter- his most important needs. Many of our most useful medicines are also ___(1)___ from plants. ___(2)___, plants add beauty and pleasure to our lives. Most people enjoy the smell of flowers, the sight field of waving grain, and the quiet ___(3)___ a forest. Not all plants are helpful to man. Some species grow in fields and gardens as weeds that choke off useful plants. Tiny hits of pollen from certain plants cause such ___(4)___ as asthma and hay fever. Other plants destroy millions of dollars ___(5)___ of crops yearly.