Many animals recognize their food because they see it.So do humans.When you see an apple or a piece of chocolate you know that these are things you can eat.You can also use other senses when you choose your food.You may like it because if smells good or because it tastes good.You may dislike sonic types of food because they do not look,smell or taste very nice.Different animals use different senses to find and choose their food.A few animals depend on only one or their senses,while most animals use more than one sense.

    Although there are many different types of food,some animals spend their lives eating only one type.The giant panda eats only one particular type of bamboo.Other animals eat only one type of food even when given the choice. A kind of white butterfly will stay on the leaves of a cabbage,even though there are plenty of other vegetables in the garden.However,most animals have a more varied diet.The bear eats fruits and fish.The fox eats small animals,birds and fruits.The diet of these animals will be different depending on the season.

    Humans have a very varied（广泛的）diet.We often eat food because we like it and not because it is good for us. In countries such as France and Britain,people eat foods with too much sugar.This makes them overweight,which is bad for their health.Eating too much red meat and animal products,such as butter,can also be bad for the health. Choosing the right food,therefore,has become an area of study in modern life.

    An official media outlet has, for the first time, published a cartoon of President Xi Jinping, with graphic details of his engagements over the past months. Cartoons can make politicians seem more friendly, says Tao Duanfang in an article for The Beijing News.

    Cartoons can leave a deep impression about a character in the minds of readers. Presidential campaign teams in countries like the US, Canada and Japan have a tradition of crafting products in the shape of politicians' caricatures.

    Tao points out that caricatures of politicians have become part of pop culture in many countries, with their purposes ranging from publicity to commercial use. Cartoons and caricatures can be used to criticize or ridicule political leaders, too. Besides, they can also help politicians introduce their political views.

    Tao says that cartoons and caricatures can bring politicians closer to the people and demonstrate the spirit of an inclusive and lively political climate, which is conducive (有利于) to social progress.

地壳中含量最多的非金属元素是（　　）