Contrary to the longheld belief that plants in natural world are always in competition，new research has found in bad environments mature（成熟的） plants help smaller ones — and thrive as a result.The research team，led by Dr.Rocio PérezBarrales studied adult and young plants in the "ecological desert" of soil in the southeast of Spain.
   The findings could have significance for those managing bad environments like coastal areas.Dr.PérezBarrales said， "What we have found surprising is that a strong large plant，called a'nurse'，shields a young one，and it also produces more flowers than those of similar size growing on their own." Dr.PérezBarrales and her team studied plant growth in southern Spain for over three months during summer and found that the young and "nurse" are more likely to thrive when grown together，compared to either plant growing alone.
   The young plants benefit from shade，more moisture and more nutrients，from the leaf litter （落葉層） of the "nurse" plants，and probably higher bacteria and fungus （真菌） in the soil.As it matures，the "nurse" plant grows more flowers than those similar ones nearby growing alone，greatly increasing its chances of producing seeds and reproducing.Besides，vegetation of "nurse" and facilitated plants with more flowers might be able to attract a greater number and variety of pollinators （傳粉昆蟲） in an area.In turn，it supports insect and soil life，and even provides a larger range of different fruit types for birds and mammals. This is the greatest achievement of the ecosystem.
   The research is likely to be of value to those who manage to protect plants in hostile and harsh environments，such as shingle and sanddune （沙丘） ecosystems，which are considered at high risk due to human action and climate change.Most home gardeners and farmers are happy with the research as well，but the findings might be of more value to those who garden in harsh places.

（1）What's the finding of the study？

A

A

A．The mature and smaller plants benefit each other when growing together.
B．Large plants sacrifice themselves for the smaller ones.
C．Young plants compete with the adults for larger space.
D．Young plants struggle to survive in harsh environments.
（2）Why is a plant called a "nurse"？

C

C

A．Because it produces more flowers.
B．Because it competes with a larger one.
C．Because it protects and helps the young.
D．Because it grows well in bad environments.
（3）What does the underlined word "This" in Paragraph 3 refer to？

B

B

A．The natural selection.
B．The biodiversity （生物多樣性）in an area.
C．The improvement of the soil.
D．The high rate of animal reproduction.（繁殖）
（4）What does the last paragraph mainly talk about？

D

D

A．The effects of the research on agriculture.
B．The shortcomings of the research at present.
C．The influence of the research on climate change.
D．The significance of the research findings in some fields.