Herbal tea has v    1     health benefits. Many people enjoy herbal tea because it can have a positive effect on energy levels. If you haven’t been feeling very well, drink some ginger tea to give your     2     (免疫) system a helping hand. Mint tea, meanwhile, is good for d    3    .

Every living thing in nature struggles to survive. Most plants are     1     by animals and people, as well as by other plants, and may have to live in difficult conditions. Plants survive by     2     to life in different environments, and by competing     3     with other living things.

Over time, some plants develop features which help them to survive in particular conditions. Plants with helpful features are more     4     to survive and reproduce. Plants without these features often die out. The process is called natural     5    .