Answer: Option D. -> Lobster, crab and spider
:
D
Lobster, crab and spider belong to PhylumArthropoda,with characteristic features like jointed appendages, exoskeleton, and a 2 or 3 segmented body (this refers to fused segments or tagmata such as the head, thorax and abdomen).

Answer: Option B. -> Hirudin
:
B
Leech belongs to Class Hirunidinea under Phylum Annelida.To feed on their hosts, leeches use their anterior suckers to connect to hosts for feeding. Once attached, the leech uses a combination of mucus and suction to stay attached, and secretes an anticoagulant enzyme called hirudin, into the host's blood stream.Due to the hirudin secreted, bites may bleed more than a normal wound even after the leech is removed.

Answer: Option D. -> Mollusca
:
D
Phylum Mollusca includes organisms which have a hard calcareous exoskeleton (shell), and are triploblastic. Some molluscs have an asymmetrical body plan, especially in the adult stage, although many of them are bilaterally symmetrical. Annelids and arthropods are usually bilaterally symmetrical, while echinoderms are radially symmetrical (in the adult stage).

Answer: Option C. -> Bilateral symmetry
:
C
Annelids and arthropods are bilaterally symmetrical, that is, the body can be divided into two identical halves only along one imaginary plane.

Answer: Option C. -> Mesoderm
:
C
Coelom or the true body cavity is lined by the mesoderm. Animals which possess coelom are called coelomates or eucoelomates.

Answer: Option C. -> Dorsal nerve cord
:
C
Notochord, dorsal hollow nerve cord, paired pharyngeal gill slits and post-anal tail are the primary chordate characters found in all members of Phylum Chordata. Feathers, lungs and diaphragm are all characters found in higher chordates such as birds and mammals.

Answer: Option B. -> (i) Malphighian tubules, (ii) Trachea, (iii) Wings
:
B
Arthropods possess jointed appendages for locomotion; some arthropods such as insects, also possess wings in addition to the jointed appendages. Respiration occurs through gills, book gills, book lungs or tracheal system. Excretion mostly happens by means of specialised structures called malpighian tubules.

Answer: Option D. -> Hair
:
D
The primary chordate characteristics include notochord, dorsal hollow nerve cord, paired pharyngeal gill slits and post-anal tail. The presence of hair is a characteristic feature of mammals.

Answer: Option D. -> All vertebrates are chordates
:
D
Invertebrates or non-chordates do not possess a notochord. Their nerve cord too, is double ventral, and not dorsal hollow like that of the chordates. Vertebrata is a sub-phylum under Phylum Chordata in which, the embryoic notochord gets replaced by a bony or cartilaginous vertebral column in the adult. All vertebrates are thus, chordates, but all chordates are not vertebrates.

Answer: Option C. -> Mollusca - Loligo, Teredo, Octopus
:
C
Loligo (squid), Teredo(shipworm) and Octopus are members of the phylum Mollusca. Physalia(portugese man of war) and Aurelia(jellyfish) are cnidarians, while Bonellia is a marine worm, considered to be a close relative of annelids. Planaria and Taenia are flatworms (platyhelminths), while Ascaris (roundworm) belongs to Phylum Aschelminthes (Nematoda). Spongilla and Euplectella are sponges (poriferans), and Pennatula (sea pen) is a cnidarian.