题目

阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。As aging population gets bigger and dementia (老年痴呆症)more common, more families are struggling with a complex question: How do you supporta loved one with dementia, especially when you have a full-time job and severalkids?Reg Urbanowski may have an answer to this pressingissue: ROBOTS.He and his team managed to develop a new type ofrobots named TP robots. Looking like stand-up vacuum cleaners attached to an iPad, they can be activated remotely via a smartphone and guided remotelyby a controller 细胞核里的染色体是由______和______组成．