Biology Test 295

Sclerenchyma tissue is known for its thickened cell walls, which are heavily fortified with lignin. This characteristic provides significant mechanical support and strength to the plant, allowing it to withstand various stresses. Sclerenchyma cells are typically dead at maturity, lacking protoplasts, and their primary function is to support the plant structurally.

Formed from six tepals arranged into two separate whorls of three parts each,Superior ovary, syncarpous, with three connate (fused) carpels and is trilocular or unilocular, actinomorphic (radially symmetric) or slightly zygomorphic (bilaterally symmetric), generally large and showy but may be inconspicuous. 

Sponges belong to the phylum Porifera. This phylum is characterized by animals that have a porous body and a simple level of organization. Sponges are primarily marine animals and are known for their unique water canal system that helps in their feeding, respiration, and excretion. Unlike the other options, where the animals are not correctly matched with their phyla (Earthworm belongs to Annelida, Jellyfish to Cnidaria, and Tapeworm to Platyhelminthes), the sponge is correctly placed in Porifera. An interesting fact about sponges is that they can regenerate from fragments, a process known as fragmentation.

Cnidarians, such as jellyfish, corals, and sea anemones, are known for having cnidoblasts (or cnidocytes), which are specialized cells that contain a stinging structure called a nematocyst. This feature is used for defense and capturing prey. Bilateral symmetry is characteristic of more advanced phyla like Chordata, the presence of a notochord defines Chordata, and a segmented body is a feature of Annelida and Arthropoda. An interesting fact about cnidarians is that they exhibit two basic body forms: the sessile polyp and the free-swimming medusa.

Platyhelminthes, or flatworms, are characterized by their bilateral symmetry, organ-level organization, and acoelomate body plan, meaning they do not have a coelom (body cavity). The presence of a coelom is not a feature of Platyhelminthes but rather of more advanced phyla like Annelida and Arthropoda. An interesting fact about Platyhelminthes is that despite their simple structure, some species have complex life cycles involving multiple hosts.

Annelids, such as earthworms, leeches, and polychaetes, are characterized by their segmented body and the presence of a coelom, which is a fluid-filled body cavity completely lined by tissue derived from mesoderm. Mollusca, Porifera, and Cnidaria do not exhibit segmented bodies; Molluscs have a non-segmented body, Porifera have a cellular level of organization without true tissues, and Cnidaria have a tissue level of organization without segmentation. An interesting fact about annelids is that their segmented body plan allows for greater flexibility and mobility.

Starfish, or sea stars, belong to the phylum Echinodermata, which is known for its members having radial symmetry (typically as adults), a water vascular system, and an endoskeleton of calcareous ossicles. Octopuses belong to Mollusca, earthworms to Annelida, and jellyfish to Cnidaria. An interesting fact about echinoderms is that they have the ability to regenerate lost limbs, and some can even regenerate an entire new organism from a single limb.

The correct order of taxonomic hierarchy from the lowest (most specific) to the highest (most general) category is Species, Genus, Family, Order, Class, Phylum (or Division for plants), and Kingdom. This hierarchical system allows biologists to organize and classify organisms in a structured manner, reflecting both evolutionary relationships and morphological similarities. An interesting fact about this system is that it was developed by Carl Linnaeus in the 18th century, and it remains the foundation of modern biological classification.

• Bacterias can be chemosynthetic, photoautotrophic and heterotrophic. Most bacteria are heterotrophs while some are photo or chemosynthetic autotrophs. 
• The bacteria is known to have the most extensive metabolic diversity because it is able to extract energy from any carbohydrate which is in its reduced form like sugar.