Water had also appeared on other planets like Mars but, unlike the earth, it had disappeared later. It was not immediately obvious that water was to be fundamental to the development of life. What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas. This produced a chain reaction, which made it possible for life to develop.
相似题推荐
【推荐1】While many of us might long to just sleep through this entire winter, humans, unlike a lot of other mammals - don’t have the capacity to hibernate (冬眠). But researchers think they have found some tell-tale marks on the fossils, which suggests that early humans may have survived the harsh winter by hibernating.
Bears have specialized metabolic (新陈代谢的) processes to protect them from this extended sleep, but sometimes this process doesn’t quite go to plan. For example, hibernators can end up with a host of diseases after hibernation if they don’t get enough food reserves before they go down for the winter. The researchers believe this may have been the circumstance of some human ancestors whose remains with deep cracks in bones were discovered in a Spanish cave called Sima de los Huesos. This deep hole is home to an incredible number of fossils, with archaeologists having discovered thousands of early humans’ skeletal remains that are around 430,000 years old and probably the ancestors of the Sima people or others.
In a paper published in L’Anthropologie, two experts argue that the fossils found in Sima de los Huesos show seasonal variations that suggest that bone growth got interrupted for several months of each year. They suggest these early humans found themselves being in metabolic states that helped them to survive for long periods of time in extremely cold conditions with limited stores of body fat.
The researchers admit the idea “may sound like science fiction”, but they point out that many mammals including primates (灵长类动物)do this. “This suggests that the genetic basis and physiology for such slow metabolism could be preserved in many mammalian species including humans," state Arsuaga and Bartsiokas.
However, Chris Stringer of the Natural History Museum in London pointed out that large mammals such as bears do not actually hibernate, because their large bodies cannot lower their core temperature enough. Instead, they enter a less deep sleep known as torpor. In such a condition, the energy demands of the human-sized brains of the Sima people would have remained very large, creating an additional survival problem for them during torpor.
1. What is Arsuaga and Bartsiokas’ attitude towards humans’ hibernation?| A．It’s quite possible. |
| B．It merely appears in science fiction. |
| C．It’s an exception to human genetics. |
| D．It solved the mystery of humans’ evolution in Europe. |
| A．They might have developed smaller brains. |
| B．Their daily sleep quality might become poor. |
| C．Their body temperature might increase rapidly. |
| D．They might suffer from life-threatening starvation. |
The condition is simple. Learn something new, and within a short period of time you’ll forget much of it. Repeat a learning session a day later, and you’ll remember more. Repeat a session two days after that, and you’ll remember even more. The key is to steadily increase the time intervals between relearning sessions.
Forgetting is an essential part of learning. Relearning strengthens earlier memories. Relearning creates different context and connections. According to Carey, “‘Some breakdown’ must occur for us to strengthen learning when we revisit the material. Without a little forgetting
According to Ebbinghaus’ chart, we conclude that ________.
| A．the best time to avoid forgetting is the sixth day after learning |
| B．we usually forget most of what we’ve learned on the sixth day |
| C．forgetting really exists almost in the whole process of learning |
| D．what has been learned will be forgotten completely in any case |
【推荐3】“When I look up at the sky, it looks a bit more amiable because it’s like, maybe somebody is waving,” said Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, US, and the study’s lead writer.
If a planet circling around one of those 1, 715 stars is home to advanced life, they could easily see that there is life here because of the oxygen on Earth. If that didn’t give it away, then the radio waves we have sent out into space would also be an indicator. In fact, human-made radio waves have already traveled through 75 of the closest stars on Kaltenegger’s list.
What does the underlined word “that” in paragraph 6 refer to?
| A．A planet circling around one of those 1,715 stars. |
| B．Advanced life. |
| C．The oxygen on Earth. |
| D．Human- made radio waves. |
