下列有关人体免疫的叙述正确的是（）

A.HIV病毒主要攻击B淋巴细胞，导致免疫功能严重缺陷

B.接种过流感疫苗的健康人不会患流感

C.非特异性免疫的第一道防线由皮肤、黏膜及吞噬细胞构成

D.T淋巴细胞受抗原刺激可增殖分化为效应T细胞和记忆T细胞

Are the following two statements about the elasticity of labor demand correct Statement 1: Labor demand is more elastic in the short run than in the long run because other factors of production are fixed in the short run. Statement 2: The more labor-intensive a firm’s production processes, the more elastic the firm’s demand for labor will be. Statement 1 Statement 2 （）①A. CorrectCorrect ②B. CorrectIncorrect ③C. Incorrect Correct

A. ①

B. ②

C. ③