阅读短文, 选择正确的答案。
The red coat is my mother's. It's very beautiful. The brown jacket is my father's. The blue pants are my brother's. They're new. The orange shorts aye my sister's. She likes them very much. The green socks are mine.
小李同学选用10×的目镜和40×的物镜，观察口腔上皮细胞临时装片，这时显微镜的放大倍数是（）
下列生态因素中，属于生物因素的是（ ）
下列说法有误的一项是（ ）
血液循环的动力器官是（ ）
