If you look outside, you probably will see some kind of insect. If your first instinct is to kill it, take a moment to think about all of the benefits insects provide to the environment. Entomologists, scientists who study insects, estimate that there are more than 800,000 species of insects found throughout the world. Only a few hundred of these insects are considered harmful. Mosquitoes, for example, are considered harmful. They bite humans and other animals, and their bites can cause skin pain and spread disease. Desert locusts also are considered harmful because they destroy crops causing billions of dollars in damage each year. However, the number of helpful insect species far outweighs the number of harmful species. Some insects make up a vital part of the food chain. Many different birds, reptiles, fish and even plants eat insects. There are also about 500 insects that people in various parts of the world eat. These insects are considered delicious food and prized for their high protein, mineral, and vitamin content. Other insects produce valuable commercial products such as silk, wax, and honey. Of all the insects, perhaps the most important are those that travel from flower to flower and pollinate  the plants they visit. Agriculture around the world would be very different without the bees, butterflies, moths, flies and wasps that pollinate many crops. In fact, nearly one-third of the food you eat depends on plants that are pollinated by insects! While it is true that some species of insects harm or annoy us, _ . You may be destroying one of the hundreds of thousands of insects that provides many benefits to human beings. According to the passage, insects are eaten in some parts of the world because   _  .
they are nutritious they are available to cook they are easy to breed they are free