在光照最强烈的夏季中午，叶肉细胞叶绿体体内的C₃、C₅和ATP的含量变化依次是[ ]

A．升、降、升

B．降、升、降

C．降、升、升

D．升、降、降

—_____ the baseball on the desk?

—Yes, it is.     [ ]

A. Does    

B. Do    

C. Is    

D. Are