①细胞核
②基因
③染色体
④DNA
⑤细胞
A:①②③④⑤
B:⑤①③②④
C:⑤①③④②
D:①④③②⑤
下列命题中假命题有( )
①若向量a→,b→所在的直线为异面直线,则向量a→,b→一定不共面;
②∃θ∈R,使sinθcosθ=35成立;
③∀a∈R,都有直线ax+2y+a﹣2=0恒过定点;
④命题“若x2+y2=0,则x=y=0”的逆否命题为“若x,y中至少有一个不为0,则x2+y2≠0”.
Progress suggests a person's ability to change the way he is living at the moment and it must ______ a better life and a better way of doing things.
如图,圆O的直径CD过弦EF的中点G,∠DCF=20°,则∠EOD等于( )