Plants are very important living things. Life could not go on if there were no plants. This is because plants can make food from air, water and sunlight. Animals and man cannot make food from air, water and sunlight. Animals get their food by eating plants and other animals. Therefore animals and man need plants in order to live. This is why we find that there are so many plants around us.

If you look carefully at the plants around you, you will find that there are two kinds of plants: flowering plants and non-flowering plants.

Flowering plants can make seeds. The seeds are protected by the fruits. Some fruits have one seed, some have two, three or four, and some have many seeds. But a few fruits have no seeds at all. An example of a fruit without seeds is the banana fruit.

Most non-flowering plants do not grow from seeds. They grow from spores(胚芽). Spores are very small. Some spores are so small and light that they can float in the air. We may say that spores are quite the same as seeds. When these spores are all on wet and shady places, they usually grow into new plants.

The term “birdbrain” is frequently used to describe a person’s lack of intelligence and good decision-making ability. However, some scientists believe it should be considered a compliment, given that many birds can perform tasks that were once considered human fields. These include making tools, solving problems, and planning for future needs. Now, Griffin, an African Grey parrot, has proved that birds may even possess better visual memories than human adults and children.

The study led by Hrag Pailian, a postdoctoral fellow at Harvard University’s Graduate School of Arts and Sciences, required the parrot to compete in the shell game against 21 adults and 216-to 8-year-old children. The popular game involves hiding a small object under one of three or more upside-down cups, which are moved around. Participants are required to accurately identify the cup under which the object lies.

The Harvard team began by placing different-colored pom-poms under four cups and moving them around. To make the task more challenging, the researchers required participants to track two, three, and four pom-poms at the same time. The cup positions we removed between zero to four times for each of the combinations.

An analysis of the results showed that Griffin outperformed the children across all levels on average. Even more impressive, the “bird brain” performed as well as, or slightly better, than the 21 Harvard students on12 of the 14 trials! It was only in the final two tests, which had the most pom-poms and most movement that the parrot fell behind the adults. However, Griffin’s performance never dropped below that of the children.

The fun experiment was part of a study conducted to test the brain’s ability to keep memories of things that are no longer in view and then updating them when faced with new information, like a change in location. The cognitive system, known as visual working memory, is one of the foundations for intelligent behavior.

Today, the most frightening living shark is the great white, which is over six meters long and bites with a force of two tonnes. Its fossil relative, Megalodon that lived about 2.3 to 3.6 million years ago, was over twice the length of a great white shark and had a bite force of more than ten tonnes.

Jack Cooper and his team used a number of mathematical methods to find out the size and proportions(比例)of this monster, by making close comparisons with a variety of living relatives that have certain similarities to Megalodon. He said, “I have always been mad about sharks. Megalodon was actually the very animal that inspired me to pursue palaeontology, the study of fossils as a guide to the history of life on earth, in the first place when I was just six years old, so I was over the moon to get a chance to study it. This was my dream project.”

Previously the fossil shark, known formally as Otodus megalodon, was only compared with the great white. Jack and his colleagues, for the first time, expanded this analysis to include five modern sharks. “Megalodon is not a direct ancestor of the great white and is equally related to several modern sharks such as the salmon shark, as well as the great white. We collected detailed measurements of all five to make predictions about Megalodon.” Dr. Pimiento said.

The researchers discovered that the babies of all these modern sharks start out as little adults, and they don’t change in proportion as they get larger. Jack Cooper said, “This means we could simply take the growth curves(生长曲线) of the five modern forms and forecast the overall shape as they get larger and larger, right up to a body length of 16 meters.”

The results suggest that a 16-meter-long Megalodon likely had a head round 4.65 meters long, a fin about 1.62 meters tall on the back and a tail around 3.85 meters high. The reconstruction of the size of Megalodon’s body parts represents a fundamental step towards a better understanding of this huge extinct shark.