The price system is a complex network _______ the prices of all the products bought and sold in the economy as well as those of a great number of services.

A．consisting of

B．consisted of

C．making up of

D．made up

随着航天技术的发展，我国开展了太空育种技术研究，并取得了丰硕成果：一个西红柿重达1．5公斤、一个青椒0．5公斤、一根水稻长了3个穗……这些技术将推动我国经济发展。这表明 [ ]

A．科学技术是第一生产力                  

B．我国科技水平已迈入发达国家行列

C．科学技术对人类有益无害                

D．我国的中心工作就是发展科学技术