If you have ever wondered how an elephant smells, scientists have the answer. Researchers have discovered that African Elephants

admin2017-08-11  22

问题     If you have ever wondered how an elephant smells, scientists have the answer. Researchers have discovered that African Elephants have the largest number of genes【C1】______smell of any mammal. Given the size of their trunks, and how important it is【C2】______their survival, it is probably unsurprising that an elephant’s nose is not only the longest in the animal kingdom, but also the most effective.
    In【C3】______, humans and other primates have a poor sense of smell. "The functions of these genes are not well known,【C4】______they are likely important for the living environment of African elephants," said author Dr Yoshihito Niimura of the University of Tokyo. "【C5】______, an elephant’s nose is not only long but also superior. " The sense of smell is【C6】______to all mammals, and they use it for【C7】______food, finding mates and locating their offspring.
    In a study published in Genome Research, scientists【C8】______the 13 mammal species and found that African Elephants have twice the number of smell genes【C9】______dogs and five times more than humans. They have around 2,000 genes alone that are associated with scent. Humans in comparison have just under 400 and some other primates even【C10】______. The study found that 20,000 genes are【C11】______for the sense of smell in mammals, of which around half are functional, but the collections【C12】______for each species. Horses have around 1,000 smell genes, rabbits around 750 and rats about 1,200.
    "The large repertoire of elephant (smell) genes might be attributed to elephants’ heavy【C13】______on scent in various contexts, including social【C14】______and reproduction," added Dr Niimura. African and Asian elephants possess a【C15】______scent organ behind each eye, and male elephants can produce a special substance during annual mating, which is characterized【C16】______increased aggressiveness. And【C17】______studies have revealed that, African elephants can reportedly【C18】______between two Kenyan ethnic groups—the Maasai, whose young men【C19】______manhood by spearing elephants, and the Kamba, who are agricultural people that【C20】______little threat to elephants through smell.
【C7】

选项 A、resorting to
B、bursting into
C、coming across
D、sniffing out

答案D

解析 本题考查动词短语作谓语,宾语为food,此处提到“所有的哺乳动物用嗅觉……食物,寻找配偶,以及找寻他们的子女”。可以看出,动物用嗅觉进行的各项日常活动,包括“寻找食物”,故选D项sniffing out“找寻”。
转载请注明原文地址:https://jikaoti.com/ti/Uvk7FFFM
0

随机试题
最新回复(0)