Biology 2023 Jamb Examination

Arthropods, such as insects, crustaceans, and arachnids, are characterized by having a segmented body, jointed appendages, and an exoskeleton made of chitin. Unlike echinoderms, they do not show radial symmetry, and unlike vertebrates, they do not have bones or a closed circulatory system. The segmented body is the defining characteristic.

The correct biological hierarchy begins with the cell as the basic unit of life, followed by tissues (groups of cells working together), organs (structures made of tissues), organisms (individual living beings), populations (members of the same species in an area), communities (different populations interacting), and ecosystems (communities plus their physical environment).

Conservation in an ecosystem means using resources wisely to prevent depletion and ensure sustainability. Sustainable fishing practices regulate harvests, avoid overfishing, and protect marine biodiversity. The other options exploit or damage natural systems.

Arteries carry blood away from the heart, and in systemic circulation they transport oxygen-rich blood to tissues. Veins carry blood back to the heart, capillaries are sites of exchange, and venules connect capillaries to veins.

Genetics is the branch of biology that studies how traits are passed from parents to offspring through DNA. Evolution and natural selection describe long-term population changes, while adaptation refers to traits that increase fitness.

Temperature is the most significant abiotic factor influencing organism distribution, as it affects metabolism, reproduction, and survival. While soil pH and light can matter locally, temperature broadly determines species ranges and biodiversity.

Animals reproduce mainly through sexual and some forms of asexual reproduction such as budding (e.g., in hydra). Sporulation is typical of fungi, algae, and some protozoa, but not of animals.

Fungi are heterotrophic organisms that absorb nutrients from decomposed organic material through extracellular digestion. They are not photosynthetic, do not form seeds, and while many are multicellular (like mushrooms), some (like yeast) are unicellular.

Viviparity is a reproductive mode where embryos develop within the female's body and are nourished directly, often through a placenta. This is seen in most mammals, providing higher survival chances compared to external development.

In the traditional Linnaean system, the kingdom is the broadest classification level. However, in modern taxonomy, the domain is used as a level above kingdom. Since the question specifies the Linnaean system, the correct answer is Kingdom.