题目详情:
发布时间:2020-06-21 09:23:59
[填空题]
Andrena Gravida is the name of a wild bee declining in the
United Kingdom and the Netherlands. A {{U}} (31) {{/U}} of months ago the
recent drop in migratory bird populations was known, based on a study
{{U}} (32) {{/U}} in the Netherlands. Now there’s more troubling news
from that part of the world: a study released today by the journal Science
reports that there’s been a dramatic loss of {{U}} (33) {{/U}} among wild
bees over the past 25 years in Holland.
There’s {{U}} (34)
{{/U}} to a 70% decline in the variety and {{U}} (35) {{/U}} of bee
{{U}} (36) {{/U}} in some areas in Britain. A loss of biodiversity is
more subtle {{U}} (37) {{/U}} an overall drop in absolute numbers of
{{U}} (38) {{/U}} or plants, but it’s still {{U}} (39) {{/U}} a
problem because the {{U}} (40) {{/U}} species in an ecosystem, the more
the system {{U}} (41) {{/U}} on each one of them, and if disease or some
other {{U}} (42) {{/U}} wipes out a species,