A:a基因产生的原因可能是其亲代产生配子时发生了基因突变
B:该细胞一定发生了染色体变异,一定没有发生基因自由组合
C:该细胞产生的各项变异均可在光学显微镜下直接进行观察
D:该细胞的变异均为可遗传变异,都可通过有性生殖传给后代
根据短文内容选择正确答案。 Mrs. Smith is Jim's mother. She loves her family very much. She goes to the store every day. She often buys food, fruit and clothes for Jim and her husband. Now many clothes are on sale at Renmin Clothes Store. They are very cheap. Mrs. Smith comes to the store and she wants to buy some clothes for her family. There they have sweaters in all colors for ¥15 each and sports shoes for only ¥28. Mrs. Smith likes the red sweater and she buys one for herself. She buys a pair of sports shoes for her son. The great T-shirts in the store are just ¥18! She buys a white one for Mr. Smith. And that's not all. The socks, in all colors, are ¥2 each. She buys the socks in many colors for her family. She is really a Rood mother and a good wife (妻子).