The space suits can be adjusted so that the team can reproduce different levels of gravity as if they________in space.

A．are　

B．has been

C．were　

D．had been

如图为纯种荷斯坦小奶牛的繁殖过程，请据图回答下列问题。

克隆动物培育过程与图示繁殖过程相比，特有的技术手段是（）技术。