【单选题】Generally, in order to be preserved in the fossil record, organisms must possess hard body parts such as shells or bones. Soft, fleshy structures are quickly destroyed by predators pr decayed by bacte...
【简答题】British government wants UK to acquire coronavirus "herd immunity." According to over 200 scientists and medical experts, however, going for “herd immunity” at this point does not seem a viable option...
【简答题】C Medical experts say most Americans do not get enough sleep. They say more Americans need to take a nap — that is to rest for a short period in the middle of the day. They give people advice to sleep...
【简答题】At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommotian fossils represent unique body forms that aros...
【简答题】Listen again and correct the eight errors in this summary of the interview. Natural gas is far less environmentally friendly than other fossil fuels like oil and coal, but it is also being replaced by...