Plant And Animal Systematics

All the given statements are correct descriptions of echinoderm characteristics, including regeneration, skin gills for respiration, and the five-part body plan.

• (A): Many echinoderms, such as sea stars, have the remarkable ability to regenerate lost arms or body parts. This is a key feature of their biology.
• (B): Respiration and waste removal in echinoderms occur through skin gills (dermal branchiae), which are extensions of their coelom.
• (C): Sea urchins are echinoderms with a five-part radial symmetry, like other members of this phylum, but they lack distinct arms, unlike sea stars.

1. Bryophytes are non-vascular plants and are divided into three phyla:
   • Marchantiophyta: Liverworts, named after the genus Marchantia.
   • Anthocerophyta: Hornworts, characterized by their horn-like sporophytes.
   • Bryophyta: Mosses, known for their leafy structures and dominance in the gametophyte stage.
2. Liverworts belong to the phylum Marchantiophyta, distinguished by their flattened, thalloid structure and oil bodies in their cells.

The number of chromosomes for each species is as follows:

• Triticum vulgare (A): This is common wheat and has 42 chromosomes, which is why it matches with II.
• Brassica oleraceae (B): This species, which includes cabbage and broccoli, has 18 chromosomes, matching with I.
• Arabidopsis thaliana (C): A model plant in genetics with 10 chromosomes, matching with IV.
• Machaeranthera gracilis (D): A flowering plant with only 4 chromosomes, matching with III.