About 80% of people do not get enough vitamin (维生素) D every day. But this vitamin is very important for your health.

Vitamin D is really important for our bones (骨骼). When we are young, vitamin D builds up our bones and makes them strong. When we are older, we still need vitamin D to keep our bones strong. Our bodies keep the vitamin D in our bones and teeth. Then we lose vitamin D as we work and exercise during the day. But our bodies can’t make vitamin D. So we have to get it from outside of our bodies.

Where can a person get this very important vitamin? Vitamin D is in foods like fish and eggs. Sometimes, vitamin D is added to bread, milk, and orange juice. Food is not the only way our bodies can get vitamin D. The sun also gives us vitamin D. If we want to be healthy, we should spend some time in the sun each day. Too much sun is not good for you, but about 15 minutes a day is usually enough. And we should be sure to eat foods that are rich in vitamin D, too.

Can you say the meaning of “zero”? Can you do addition and subtraction (加法)? Most people can. But do you know bees can do these things too? A study shows that bees have even greater math abilities. After some training, they can know the difference between even numbers (ending in 0, 2, 4, 6 and 8) and odd numbers (ending in l, 3,5, 7 and 9).

Some Australian scientists put up different cards with an odd or even number of triangles (三角形). They used the numbers 1 to 10. Then they trained the first group of bees to choose odd numbers and the second group to choose even numbers. If a bee flew to the right card, it would get sugar water; if not, it got bitter water.

In a short time all the bees knew what odd numbers or even numbers were. They could fly to the right numbers 80% of the time. After that, the scientists added new cards with the numbers 11 and 12. The bees never saw the numbers in their training before, but they could choose rightly 70% of the time. Surprisingly, the bees even learned odd numbers more quickly than humans.

How did the bees learn the numbers so fast? Scientists believe that finding the answer will help them build better and faster computers. But they don’t have a clear idea yet. In fact, a bee’s brain is much smaller than ours!

Do you know about bioplastic (生物塑料)? It is a kind of plastic. But it is different. Normal plastic is made from chemical materials and takes a very long time to degrade. But bioplastic is good for the environment. It is made by using bacteria (细菌) to process natural sources like vegetable oils, corn or sugar. It can degrade more easily.

But there is a problem with bioplastic. The “food” that bacteria eat is also what we eat. This means that bacteria are competing against humans for the same resources.

Now scientists have found a new way to make bioplastic using two kinds of bacteria and sunlight, according to Newsweek.

One of the bacteria is called synthetic cyanobacteria (合成蓝藻), which can use sunlight to produce sugar. The other kind is Halomonas boliviensis (玻利维亚盐单胞菌), which lives in the salty waters of Bolivia. It eats the sugar that the first bacteria produce and then it can produce polymers (聚合物). Polymers are used to create bioplastics. The way the bacteria store polymers is similar to how humans store fats.

Producing bioplastic with these two bacteria has many advantages. It is 20 times faster than the normal way we produce bioplastic. Also, using these two bacteria saves resources.

First, producing large amounts of bioplastic requires corn and sugar, which are used to feed normal bacteria. And growing corn and sugar needs farmland. But these two special bacteria can just use sunlight. The land that is saved can be used to grow food for humans.

Besides, this process doesn’t need rich land or clean water at all, scientists said to Newsweek. The next challenge scientists face is that they want to put their lab research into real-world practice. By doing this, bioplastic made with these two bacteria can be widely produced in the future.