Reading comprehension Line For many people, mushrooms are strange, colorless, incomprehensible plants that should be avoided. Quaint tales and scary stories surround mushrooms because some are extremely poisonous. In reality, however, mushrooms are fungi that are simple plants without developed roots, leaves, stems, flowers, or seeds. They grow in wetlands, grassy meadows, and woods. Certain types of mushrooms are delicious and are included as ingredients in many recipes and trendy snacks. For example, morels are considered one of the choicest foods, and truffles, related to morels, are highly prized in Europe. Their shape is tube-like, and they remain entirely underground, a foot or more below the surface. In the old days, dogs and pigs were specially trained to hunt them by scent.                Mushrooms stand out among other plants because they have no chlorophyll and cannot generate their own nourishment. The part of the fungus that rises above the ground is the fruiting body, and the vegetative part that produces growth is hidden under the ground. It can be usually dug up in the form of dense, white tangled filaments, which, depending on the food supply and moisture, can live for hundreds of years. In fact, mushrooms, as well as the rest of the fungus genus species, are one of the few remaining simple plants that are believed to be among the oldest living organisms. When their environment is not conducive to growth, filaments stop proliferating and can lie dormant for dozens of years. Although mushrooms are rich in flavor and texture, they have little food value. Picking mushrooms requires a thorough knowledge of environments where they are most likely to grow and an ability to tell between edible and poisonous plants. Most mushrooms thrive in temperatures from 68° to 86° (F) with plenty of moisture, and nearly complete darkness produces the best crop. The entire mushroom should be picked, the stem, the cap, and whatever part that is underground. Brightly colored mushroom caps usually indicate that the plant is not fit for consumption, and the more the mushroom attracts attention, the more poisonous it is. Mushrooms with beautiful red or orange spotted caps that grow under large trees after a good rain are particularly poisonous. If milky or white juices seep from a break in the body of plant, chances are it should not be picked. Old mushrooms with brown caps are also not very safe. 

In line 7, the word “Their” refers to