阅读判断。根据短文内容，判断下列句子的正与误。

Long long ago, there was no paper in the world. People had to write characters(汉字) in bamboo slips or stones.Then there was a man named Cai Lun who was a Chinese man. He made people use all kinds of things to invent paper. From then on, people can use paper to write on. Paper is a great invention. We always remember the great inventor Cai Lun. Nowadays paper is very useful in our work, study and our life.It really means a lot to human beings

把上面的3个 看作一份，下面的每3个 也看作一份，那么下面6个 可以看作____份．

6个 是3个 的____倍．

6里面有____ 个3，6是3的____倍．

算式：____÷____=____

某二倍体植物染色体上的基因B₂是由其等位基因B₁突变而来的，如不考虑染色体变异，下列叙述错误的是（　　）