本题目来源于试卷: IB ESS Unit 2: Ecosystems & Ecology，类别为 IB环境系统与社会
[单选题]
Leaf stem longer than 2 cm go to 2
Leaf stem shorter than 2 cm go to 3
A. Edges of leaf serrated
B. Edges of leaf smooth
C. Leaf length almost same as its width
D. Leaf more than 2 times as long as it is wide
参考答案: D
本题详细解析:
In order to know what organisms are found in the world around ussn7j +1xht9et, we have created identificatioxhne7s t9t1+j n keys to help us in this task.
The most efficient way to set up a key is to split the group of possible species into two at each step. As you answer each question you are guided to the next one and eventually end up with the name of the organism you are trying to identify. This key uses leaves to identify trees as each species of tree has a particular shape of leaves.
We start at question 1. The stem is shorter than 2 cm, so we go to question 3. The leaf is more than 2 times as long as it is wide, so it is species D.
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