Classification of Animals Test - 4

The blood of the annelids usually contains hemoglobin, a red oxygen carrying pigment. In some annelids, erythrocruorin is present. It is a large oxygen-carrying protein.

Ascaris does not show metamerism.  It is a monogenetic parasite which completes its lifecycle in a single host. Ascaris shows separate male and female worms with sexual dimorphism and a rhabditiform larva stage in its life cycle. Thus, the correct answer is option A.

Annelids are segmented worms. Earthworms belong to this phylum because their bodies are sectioned; creating the ridged or ringed appearance that gives the "ringed worms" of this phylum their name.

Phylum Arthropoda of the kingdom Animalia is characterised by the jointed legs and exoskeleton, It consists of:

Apis (honey bee), Bombyx (Silkworm), Laccifer (lac insect), Anopheles, Culex and Aedes (mosquiotes), Locusta (locust), Limulus (king crab). Thus, the correct answer is option A.

Butterflies belong to the phylum 'Arthropoda', to which insects belong. Butterflies and moth belong to the order Lepidoptera. Lepidos is Greek for "scales" and ptera means "wing". These scaled wings are different from the wings of any other insects. So, the correct option is 'Arthropoda'.

Round worms are unisexual animals and they belong to phylum Nematoda or Aschelminthes. It is bilaterally symmetrical, triploblastic pseudocoelomate.

Characteristics of phylum Annelida are as follows:

Cylindrical, segmented, bilaterally symmetrical and triploblastic organisms.

Coelomate, often divided by internal septa, the body possesses a through the gut with mouth and anus. 

Closed circulatory system. 

Reproduction is sexual but sexes are not separate (hermaphrodite).

Locomotion is through setae.

For example, earthworm, leech, nereis, etc.

When the bodies of organisms are made up of segments and the segments are similar to each other, then this type is known as metameric segmentation. Annelid exhibit metameric segmentation.
Annelids are all bilaterally symmetrical animals. They are triploblastic meaning have three embryonic tissue layers as ectoderm, mesoderm and endoderm. Nearly all annelids have a fluid-filled cavity between the outer body wall and the gut and this is referred to as coelom and thus is coelomates.

The phylum Annelida is characterised by the presence of a segmented, tube-shaped body. Earthworm belongs to the phylum Annelida.