Ants

Ants don’t have ears. But that doesn’t mean they are deaf (聋的). They hear by feeling vibrations (震动) in the ground. Ants have special sensors (传感器) on their feet and legs to sense signals from their surroundings.

Emus

Emus can walk forward but not backward. It is not clear why this bird cannot walk backward. Many have suggested that its knee joint (关节) prevents it from moving backward.

Birds

Did you know this?Birds can’t be brought into outer space because birds need gravity (重力) to swallow (吞咽) food. NASA did an experiment with a bird in space. After the spaceship reached orbit (轨道), the bird did not eat anything. It also had some balancing problems.

chinchillas

Water is one of the deadliest enemies (死敌) of chinchillas. Chinchillas should not get wet because they have very dense (浓密的) fur that is extremely difficult to dry, causing a risk of fungus (真菌) and bacterial (细菌) infection, which can in turn, create a bigger problem for their skin.

After graduating from middle school, many students grow very fast, especially boys. And the teachers have to look up at their faces to show love for them. Why do they grow so fast?

Height is just one of the thousands of features your genes(基因) decide. In fact, because you have two parents, your genes provide you a height that usually lands somewhere between the height of each parent. If both your parents are tall, then perhaps you will be tall, too. But if you have questions about how tall you’re going to be, ask your doctor if he or she can help you find it out.

But genes don’t decide everything. For example, eating an unhealthy diet can keep you from growing to your full potential(潜力). Getting enough sleep and exercise will help you grow to the right height.

No doubt you’re wondering how fast you should grow. It depends. There’s no perfect or right answer. Kids grow about 5 cm a year between age 3 and the time when they start puberty（when your body starts changing and becoming more grown up. ）

Don’t be scared if you seem to have grown a lot in a very short time. Everyone has a growth spurt(高峰) during puberty. The age for starting puberty is about 10 for girls and 11 for boys. But it can be earlier or later between 7 and 13 for girls and 9 and 15 for boys.

You’ll usually begin to notice that you’re growing faster about a year or so after your body starts to show the first changes of puberty.

Do you know that it is your own immune system(免疫系统) working against the virus that makes you uncomfortable when getting a cold, but not the virus itself? So when you have got a strong immune system and the virus is strong enough too, you will possibly get terrible cold symptoms (症状)?

Vitamin C won't stop a cold

It is claimed that Vitamin C helps by increasing white blood cells. However, many tests have shown that it does not prevent colds. At best, it only slightly reduces the rime of symptoms.

Staying indoors won't protect you

One of the most likely sources of cold viruses is your computer mouse or desk. A study of the cold virus in offices found that 47% of desktops, 46% of computer mice and 45% of telephones had cold viruses on them.

Wrapping up warm won't protect you

Colds are more common in autumn and winter. That's because the cool, wet and cold weather drives people indoors, where viruses may more easily jump from one person to another. And the distinct peak in colds(感冒高峰) is in September and early January, which is likely due to the return of students to schools and colleges after the summer and winter vacation.

Old granny's chicken soup is right.

Granny's chicken soup is an old cure for colds since a long time ago. Scientists say it is true. Chicken soup does help cure a cold. Many canned soups are just efficient as homemade ones.