A:在“观察DNA和RNA在细胞中的分布”实验中,用质量分数为8%的盐酸处理的口腔上皮细胞仍是活细胞,只是其膜的通透性增强
B:在“观察DNA和RNA在细胞中的分布”实验中,需将两滴吡罗红染色剂和甲基绿染液先后滴在载玻片上
C:与甲基绿发生结合的核酸分子只分布在细胞核中
D:核酸在生物体的遗传、变异和蛋白质的生物合成中具有重要作用
有关墨累河的叙述,错误的是( )
《杯弓蛇影》典故中说的是客人见杯中的弓影,以为是蛇在酒中,勉强喝下,即疑虑而生病,明白真相后,疑虑消失,病马上就好了。这个故事告诉我们一个道理是( )
某兴趣小组以“新中国科技世界之最”为课题,开展研究,收集到以下资料,其中最适合入选的是( )
have, relaxing, after, classmate, sport, difficult
I'm Kate. I like sports very much. I ____ a ping-pong bat, a ping-pong ball and a basketball. I always play basketball ____ class. It's easy for me and it's ____. Some of my ____ like baseball. I think it's ____ and I can't play it well. but I like watching it on TV. It's good for me to do ____ every day.