在一片森林中，有土壤、阳光、水、空气，还生活着各种植物、动物和微生物，对于生活在森林中的动物来说，下列属于生物因素的是（  ）

增加：在缺词处加一个漏字符号（∧），并在下面加上该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写上修改后的词。

注意：1）每处错误及其修改均仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

    When I first came to England, I know little English. As you can probably guess it, my life was difficulty for a time. Simple tasks like ordering food or take a taxi were quite stressful. I signed up for classes and studied on my own as well, so I made poor progress. I became very discouraging. Finally, I found best way to learn English was to make friends with native speakers and spend time with them. I appreciated playing in a band with an English woman which became one of my best friend in London. My English improved great by hanging out with her.

下列与太阳辐射有关的是（    ）