[解析]
1.B 根据Their leaves grow on the top and flowers seldom come out.他们的叶子长在上面,花很少出来.可知苏铁花一年开一次是错误的.故答案为B.
2.A 根据Surprisingly,the danger is from the people who love them most.令人惊讶的是,危险来自最爱他们的人.可知苏铁爱好者使苏铁处于危险之中.故答案为A.
3.A 根据It is Wood's Cycad.Someone found it in a forest in 1895.It is the only one of its kind."这是Wood's Cycad.1895年有人在森林里发现了它.这是唯一的一种.可知1895年发现的Wood's Cycad是唯一的一种.故答案为A.
4.B 根据they have become a symbol(象征)of wealth and position( 地位)in society.它们已经成为社会财富和地位的象征.可知苏铁已经成为幸运和健康的象征是错误的.故答案为B.
5.A 根据At the same time,people around the world should also work together to protect the plants.同时,世界各地的人们也应该共同保护这些植物.可知作者希望人们联合起来拯救这些植物.故答案为A.