下列生物中属于生产者的是: [ ]
A.青菜
B.金鱼
C.细菌
D.蘑菇
答案:A
抗原的基本性质是()
A.异物性和特异性
B.免疫原性与免疫反应性
C.抗原性与异物性
D.理化复杂性与特异性
E.异物性和免疫反应性
(2013 ·陕西宝鸡二模)—You don't seem to be quite yourself today.What's wrong?
—Oh, I'm suffering from a cold.Nothing serious ________.
A.yet
B.indeed
C.though
D.anyway