A:was broken out; was lasted
B:broke out; lasted
C:happened; was continued
D:was happened; continued
关于动物生殖和发育的叙述,正确的是( )
某干旱半干旱地区人口持续增长。下图示意该地区25人/km2等人口密度线的变化。据此回答下列问题。