The females in a group of wild chimpanzees are the first non-human primates to be documented experiencing menopause（更年期）. The finding， recently published in Science， deepens the mystery of why a handful of mammals — including humans and toothed whales — evolved extended female lifespans beyond their reproductive years.

“There’s so many species who just more or less reproduce until they keel over，” says Tobias Deschner， a primatologist at Osnabrück University in Germany. The riddle， he says， is why a select few buck this trend， ceasing reproduction long before they die.

Researchers followed 185 female members of the Ngogo community of chimpanzees in Kibale National Park， Uganda from 1995 to 2016. The data revealed that， in a pattern similar to that in other chimpanzees and humans， the number of births declined after 30 years old， and ceased altogether by age 50.

Yet， several female chimpanzees continued to live post-reproductive lives， sometimes well into their 60s. Ngogo females spend around one-fifth of their adult lives in this post-reproductive period， roughly half as long as that of hunter-gatherer humans. That number was much larger than the team expected， says Brian Wood， an anthropologist at the University of California， Los Angeles.

The female chimpanzees experience a hormonal（荷爾蒙的） transition similar to that seen in humans. Following post-reproductive Ngogo females to collect samples of urine as it showered from the trees， the scientists found oestrogen and progestin levels falling， paired with follicle-stimulating hormone and luteinizing hormone rising， which control ovulation（排卵） and renewal of the uterine lining after menstruation.

Deschner says that the research highlights the value of long-term observational studies. “The longer such a site exists， the more valuable the data becomes that comes out of that site，” he says. “Just keeping these projects alive is a valuable investment.”

（材料來自Nature網(wǎng)站，有刪改）

1. Scientists find from their studies that female chimpanzees ______.

A. have the period of menopause

B. stop giving birth at young age

C. keep reproducing in their life

D. start menopause earlier than whales

2. According to the research， what causes female chimpanzees’ reproductive decline？

A. Natural aging. B. Hormonal fall.

C. Environmental factors. D. Terrible illness.

3. What should scientists do about observational studies according to Deshner ？

A. Stop them if necessary.

B. Just continue their value.

C. Record their existence.

D. Often change the site for them.

4. How does the author support the theme of the text？

A. By giving examples.

B. By stating arguments.

C. By explaining statistical data.

D. By providing research results.

1. A。解析：細(xì)節(jié)理解題。材料第一段的第一句提到“一群野生黑猩猩中的雌猩猩是第一批被記錄到經(jīng)歷更年期的非人靈長類動(dòng)物”。A項(xiàng)“有更年期”與材料內(nèi)容相符，故選A。

2. A。解析：細(xì)節(jié)理解題。材料第三段的第二句提到“數(shù)據(jù)顯示，與其他黑猩猩和人類的情況相似，這些黑猩猩在30歲后生育能力有所下降，到50歲時(shí)完全停止生育”。A項(xiàng)“自然老化”與材料內(nèi)容相符，故選A。

3. B。解析：推理判斷題。材料最后一段中提到“Deschner說，這項(xiàng)研究突出了長周期觀察研究的價(jià)值”“這樣一個(gè)觀察點(diǎn)持續(xù)的時(shí)間越長，從中得出的數(shù)據(jù)就越有價(jià)值”“光是讓這些項(xiàng)目存活下去就是一項(xiàng)有價(jià)值的投資”，據(jù)此我們可以推斷Deschner是想讓科學(xué)家們把這些項(xiàng)目繼續(xù)做下去，因?yàn)樗J(rèn)為有價(jià)值。故選B。

4. D。解析：推理判斷題。本題要求判斷作者是如何支撐文章的主題的。A項(xiàng)“通過舉例”似是而非，材料雖然提到在烏干達(dá)做的研究，但這并非簡單的舉例，而是嚴(yán)謹(jǐn)?shù)膶?shí)地研究；B項(xiàng)“通過陳述論點(diǎn)”顯然不符合材料內(nèi)容，這篇材料并非僅僅通過論述驗(yàn)證作者的觀點(diǎn)，而是有科學(xué)實(shí)地研究作為支撐；C項(xiàng)“通過解釋統(tǒng)計(jì)數(shù)據(jù)”，材料中并未提及；D項(xiàng)“通過提供研究結(jié)果”符合實(shí)際，材料多處引用科學(xué)家的研究結(jié)果和實(shí)地觀察研究結(jié)論。故選D。