Dichotomous Keys

The diagram shows a flowering plant.

Use the key to identify the plant.

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2018//Paper2_3/Q4

jagged 锯齿状的；参差不齐的

The diagram shows part of a flowering plant.

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2018//Paper2_2/Q3

petal 花瓣

每个节点做一次选择，逐级向下

parallel vein 平行叶脉

netted vein 网状叶脉

The diagram shows part of the classification of the animal kingdom with an example of each group. Which pair of animals have the most recent common ancestor as suggested by the classification?

• A. centipede and carp

• B. flea and frog

• C. lizard and parrot

• D. spider and rat

Answer explanation

IGCSE BIOLOGY 2017//Paper2_2/Q3

图上距离最近，就是有most recent common ancestor最近的共同祖先。

Tags

NGSS.MS-LS4-2

Use the key to identify the animal shown in the diagram.

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2016//Paper2_1/Q3

4对腿。

Tags

NGSS.MS-LS4-2

The diagram shows an animal

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2015//Paper1_2/Q4

rounded bill 圆形的喙（鸟嘴）

pointed bill 尖嘴

webbed feet 蹼脚;

Tags

NGSS.MS-LS4-2

The diagram shows a flower seen from above.

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2015//Paper1_1/Q4

petal 花瓣，stamen 雄蕊

petals joined 花瓣连接在一起

petals separate 花瓣分离

Keys are used in biological identification.

Which statement may appear in a key and alone could identify one of the plants in the diagrams?

• A. The plant has a single deep root with small branches.

• B. The plant has many similar roots, arising from a single point.

• C. The plant has one flower on the stem.

• D. The plant has pointed leaves.

Answer explanation

IGCSE BIOLOGY 2013//Paper1_1/Q4

B，C，D是图中两个或多个植物的共同点。

题干要求给出一个独特的特征直接区分出4个植物中的一种。选A，它描述的是从左往右第3株。

Tags

NGSS.MS-LS4-2

The diagram shows a fish.

• A

• B

• C

• D

Answer explanation

IGCSE BIOLOGY 2012//Paper1_1/Q4

black stripe 黑色条纹

caudal fin 尾鳍

anal fin 臀鳍

pectoral fin 胸鳍

pelvic fin 腹鳍

dorsal fin 背鳍

Tags

NGSS.MS-LS4-2