Adiantum is called "walking fern" due to :-Power of locomotion    Vegetative reproductionMotile antherozoites     All the above

Breakdown of the Problem

To determine why Adiantum is called "walking fern," we need to analyze the options provided.

Relevant Concepts

1. Power of locomotion: This implies movement, which might suggest the ability of the fern to move from one place to another.
2. Vegetative reproduction: This indicates that the plant can reproduce asexually, potentially allowing parts of it to grow roots and form new plants at some distance from the parent.
3. Motile antherozoites: This refers to the sperm cells of the fern that can move towards the egg for fertilization.

Analysis and Detail

1. Power of locomotion: In plants, this concept is largely metaphorical, as true locomotion is not common. The term might refer to the ability of fronds to extend and create new growth points.

2. Vegetative reproduction: Walking ferns can reproduce vegetatively; segments of the frond can take root and establish new plants, which gives the impression of "walking" as they spread.

3. Motile antherozoites: Ferns typically have swimming sperm. This is a characteristic of many ferns, including Adiantum, but does not specifically relate to the "walking" aspect.

Verify and Summarize

Among these options, the most relevant reason for the name "walking fern" pertains to its ability of vegetative reproduction, which allows it to propagate and spread across the ground.

Final Answer

Adiantum is called "walking fern" chiefly due to its vegetative reproduction capability, which enables segments of the plant to root and give rise to new plants, creating a walking or spreading effect.