“远看山无色，近听水有声，春去花还在，就是看不清。”是对哪种自然灾害的形象描述？（  ） A.
火灾 B.
飓风 C.
雾霾 D.
洪水

A．It is the executioner caspases during apoptosis.
B．It cleaves many targets in the cells undergoing apoptosis.
C．During apoptosis once caspase 3 was activated, its activity reached maximum within 20min.
D．All of the above