题干

某岛屿上生活着一种动物,其种群数 量多年维 持相对稳定。该动物个体从出生到性成熟需要6个月。下图为某年该种群在不同月份的年龄结构(每月最后一天统计种群各年龄组成的个体数)。关于该种群的叙述,错误的是

A:该种群10月份的出生率可能为零

B:天敌的迁入可影响该种群的年龄结构

C:该种群的年龄结构随着季节更替而变化

D:大量诱杀雄性个体不会影响该种群的密度

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D

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    If life is a beach, then a village in Ireland has come back from the dead after the sand returned 33 years later due to a freak tide.

    Dooagh beach on Achill Island in the west of Ireland, was washed away in 1984 after storms hit the area, leaving a rocky foreshore. The tourists left, causing the hotels and guesthouses as well as the cafes to close down. But in April this year, the sand returned over a ten-day period caused by an unusually high tide that deposited hundreds of thousands of tons of sand along the 300m beach, bringing the beautiful beach back to its former glory.

    Emmet Callaghan from Achill Island Tourist Office told the journalist that the people of the island were excited at the beach's reappearing. “It's so nice for the villagers to have their beach back. It is an incredible example of the force and power of nature and how the coast can change in a matter of days. Yesterday we had traffic block here in the village with cars and people coming from all over Ireland and the UK to see our new beach,” he said. “The people here have always spoken about their days on the beach and how they enjoyed it as children. To have it back with their kids is unbelievable. Now locals are hoping that the beach is given the blue flag status. We already have five blue flag beaches and hopefully, if we keep our beach here, we'll have a sixth.”

    Dr Ivan Haigh from the University of Southampton said there were two explanations as to why the beach has reformed. “It could be a change in sediment (沉积物) supply, from further up or down the coast which has brought a fresh amount of sediment to the beach,” he said. “It could also be due to a change in environmental conditions, either a change in the wave climate or a series of tides that have provided the ideal conditions for this beach to reform.”

    The tourism office and locals hope the new beach will stay, at least for the summer of this year.