Biology 2007 Jamb Examination

C. Drought

Competition occurs when resources are limited. Drought reduces the availability of water and food, increasing competition among members of a population for survival.

A. Lamarck

Lamarck's theory of inheritance of acquired characteristics suggested that traits developed during an individual's lifetime, such as enlarged muscles due to exercise, could be transmitted to offspring. Modern genetics shows this is incorrect.

B. Attract mates

The gular fold in lizards is an extendable throat flap. Males display it to attract females during mating season, signaling health and readiness to reproduce.

C. Lung fish

Lung fish can survive dry seasons by burrowing into mud and entering a state of aestivation, reducing metabolic activity until water returns.

B. Adrenal gland

The adrenal glands are located atop the kidneys and secrete hormones like adrenaline and cortisol, which regulate stress response, metabolism, and blood pressure.

A. Chlorophyll and carotenoids

Photosynthetic pigments such as chlorophyll a, chlorophyll b, and carotenoids absorb light energy to drive photosynthesis in plants. Chloroplasts contain these pigments, but are not pigments themselves.

A. No cambium

Monocot stems lack a vascular cambium, so they do not undergo secondary growth. Dicot stems possess cambium, which allows thickening over time.

D. Osmosis

Guard cells control stomatal aperture via turgor changes. Water enters or leaves the guard cells by osmosis, causing them to swell or shrink and thereby opening or closing the stoma.

B. Phosphorus

Phosphorus deficiency in plants leads to stunted growth, dark green leaves, and poor root development because it is essential for energy transfer (ATP) and nucleic acid synthesis.

A. Fats, proteins and carbohydrates

The pancreas secretes lipase (fats), amylase (carbohydrates), and proteases such as trypsin and chymotrypsin (proteins) into the small intestine to aid digestion.