Diversity in Living Organisms Test - 90

Most of the amphibians lay eggs in water because the eggs produced do not have amnion which makes the eggs receptive to heat and dryness. So on laying in water, they can prevent this dryness. Also, amphibian eggs do not have a hard protective shell like bird or reptile eggs. Most amphibian eggs become much bigger after they are laid because the eggs absorb water and swell to several times their original volume by diffusion.

Aschelminths or Nemathelminthes are either free-living or parasitic animals.

• The Giant Intestinal roundworm species belonging to the phylum Nemathelminthes is an endoparasite living in the human intestine. 

• These roundworms cause a disease called Ascariasis. 

• They usually live inside the intestine and causes obstruction to the intestinal passage.

• So, the correct answer is Nemathelminthes.

• Protostomes are bilaterally symmetrical triploblastic animals.
  
• They are so called because in them the mouth is formed first and then the anus.
• When the cleavage planes are not parallel or perpendicular to the animal-vegetal pole axis of the ova or egg it is called spiral cleavage.
• In Protostomes, the cleavage takes place at oblique angles which form a spiral pattern of daughter blastomeres.
  
• This type of cleavage pattern is characteristic of Protostomes.
• So, the correct answer is 'Spiral'.

1. Planaria are common to many parts of the world, living in freshwater ponds and rivers. Some species are terrestrial and are found under logs, in or on the soil, and on plants in humid areas.

Zygote formed In bryophytes is the beginning of the sporophytic generation.
It will repeatedly divide through mitosis and later differentiate to form a sporophytic plant body. Sporophyte comprises of stalk and capsule in case of bryophytes. Sporangium is present within the capsule that contains spore mother cells which will undergo meiosis to form haploid spores. Later these spores germinate to produce a gametophytic body.
So, the correct option is D.

• Segmentation is the division or differentiation of the body into distinct portions called segments. It is first observed in the phylum Annelida.
• The annelids are also known as the ringed worms or segmented worms, are a large phylum, with over 22,000 living species including ragworms, earthworms, and leeches.

So, the correct answer is option C.

Any wormlike invertebrate of the phylum Pentastomida (or subphylum of Arthropoda), having two pairs of hooks at the sides of the mouth: all are parasitic, some in the respiratory tracts of mammals.