Write down the characteristic features of phylum Porifera and Nematoda.

Body Symmetry: Asymmetrical or radially symmetrical.
Body Organization: Cellular level of organization.
Germ Layers: Diploblastic (two germ layers: ectoderm and endoderm).
Body Wall: Numerous pores (ostia) for water inflow and a single large opening (osculum) for water outflow.
Skeleton: Internal skeleton made of spicules (calcareous or siliceous) or spongin fibers.
Digestion: Intracellular digestion.
Circulation: Water canal system for circulation of water, food, and oxygen.
Respiration and Excretion: Diffusion through the body surface.
Nervous System: Absent or poorly developed, with no specialized nerve cells.
Reproduction: Asexual (budding, fragmentation, gemmules) and sexual (most are hermaphrodites).
Habitat: Mostly marine, few freshwater.
Examples: Sycon, Spongilla, Euspongia

Body Symmetry: Bilateral symmetry.
Body Organization: Organ-system level of organization.
Germ Layers: Triploblastic (three germ layers: ectoderm, mesoderm, and endoderm).
Body Wall: Body covered with a tough, flexible cuticle that is molted periodically.
Body Cavity: Pseudocoelom (false body cavity) filled with fluid.
Digestion: Complete digestive system with a mouth and anus.
Circulation: No specialized circulatory system; nutrients and gases transported through the pseudocoelomic fluid.
Respiration: Aerobic respiration through the body surface or anaerobic respiration in some parasitic forms.
Nervous System: Simple nervous system with a nerve ring and longitudinal nerve cords.
Reproduction: Mostly sexual with separate sexes (dioecious); some are hermaphrodites or parthenogenetic.
Habitat: Free-living in soil, freshwater, and marine environments; many are parasitic in plants and animals.
Examples: Ascaris, Wuchereria, Enterobius (pinworm)

Discuss scientific method as a tool of acquiring knowledge. Compare it with various steps in the research process