Kingdom Animalia

The correct option is (C) and

Pheretima, a member of the phylum Annelida, is organized at the organ system level.

Phylum Fasciola Platyhelminthes is organized at the organ level.

Spongilla belongs to the phylum Porifera and has a cellular aggregate level of organization.

Obelia is a phylum. An organism at the tissue level is present in Coelenterata.

The number of cells in multicellular organisms ranges from millions to trillions. These cells all carry out distinct tasks. In the body, tissues are made up of all the cells that have been trained to carry out certain tasks. Thus, a set of cells at a certain location in the body perform a specific function. Similar to this, several cell groupings inside an organism perform various roles. The division of labour in multicellular creatures is what gives rise to this.
 

Discover more from this chapter: Animal Kingdom
 

Let's evaluate each statement regarding Class Aves:

Forelimbs are modified into wings and hindlimbs are modified for walking and swimming:

• This is correct. In birds, the forelimbs are modified into wings, which are used for flight. The hindlimbs are adapted for various purposes, including walking (in terrestrial birds) or swimming (in aquatic birds like penguins).

Heart is completely four-chambered:

• This is correct. Birds have a four-chambered heart, which allows for efficient separation of oxygenated and deoxygenated blood, supporting their high metabolic rate.

They are homeotherms:

• This is correct. Birds are homeothermic (also known as endothermic), meaning they maintain a constant body temperature, irrespective of the external environment.

They are oviparous and development is direct:

• This is correct. Birds lay eggs (oviparous) and undergo direct development (meaning the young birds resemble adults after hatching).

All the statements regarding Class Aves are correct.

The correct answer is (D) : All are correct.