It still puzzles the science world why some mammals produce their young ______ and hatching while

others _____ to young babies.     [ ]

A. lying eggs; giving birth            

B. by laying eggs; by giving birth  

C. by laying eggs; give birth            

D. laying eggs; giving birth

对与群众利益密切相关的重大事项实行公示、听证等制度，有利于(　　)

①增强决策透明度和公民参与度　②集中学者的智慧，提高决策的科学性

③扩大公民的政治权利　       ④决策利民

A．①②

B．①③

C．②④

D．①④