Biology 2006 Jamb Examination

D. Hepatic portal vein

The hepatic portal vein begins with capillaries in the digestive organs and ends in liver capillaries, transporting nutrients for processing before reaching the systemic circulation.

B. Pericycle

The pericycle is the layer just inside the endodermis and surrounds the vascular bundles. It gives rise to lateral roots and contributes to secondary growth in plants.

D. XX and XY

Females have XX sex chromosomes, while males have XY. Other forms such as XXY or XYY are abnormalities associated with genetic disorders.

D. Are better adapted to changes

Variation increases genetic diversity, allowing some individuals to survive better under environmental changes, thereby ensuring survival of the species.

B. Alleles segregate independently

The law of independent assortment states that alleles of different genes are inherited independently of one another, creating genetic variation.

B. An increase in population size

Competition becomes more intense as population size increases because more individuals demand the same limited resources such as food, space, and mates.

A. Sweat gland

Sweat glands help regulate body temperature by releasing sweat, which evaporates and cools the skin, especially in hot conditions or after exercise.

D. Transport organic materials in and out of the cells

The Golgi apparatus modifies, packages, and transports proteins and lipids for use inside or outside the cell.

C. Gametophyte

In bryophytes like mosses, the gametophyte (haploid) phase is dominant and independent, while the sporophyte depends on it for nutrition.

A. Comparative anatomy

Ferns are considered more advanced than mosses based on comparative anatomy. Ferns have vascular tissues (xylem and phloem) which mosses lack, enabling them to grow taller and transport water efficiently.