A plant species exhibits a high rate of water loss despite having thick cuticles. What adaptation is likely responsible for this?
Increased stomatal density leads to higher water loss through transpiration, despite thick cuticles, as more stomata allow greater evaporation.
The symbiotic relationship between Rhizobium bacteria and leguminous plants is best described as
Mutualism occurs as Rhizobium fixes nitrogen for the plant, while the plant provides nutrients and shelter to the bacteria.
The primary role of chlorophyll in photosynthesis is to
Chlorophyll absorbs light energy, which is then used to drive the synthesis of glucose during photosynthesis.
In humans, the hormone responsible for the development of secondary sexual characteristics in males is
Testosterone, produced by the testes, drives the development of male secondary sexual characteristics like facial hair and deep voice.
The type of reproduction in yeast that involves the formation of a small bud is called
Yeast reproduces asexually by budding, where a small bud forms on the parent cell and eventually separates.
The type of root system that is most effective in preventing soil erosion on a slope is
Fibrous root systems, with their dense network of roots, anchor soil effectively, preventing erosion on slopes.
The type of bond that holds the two strands of DNA together in a double helix is
Hydrogen bonds form between complementary nitrogenous bases (A-T, C-G), holding the two DNA strands together in a double helix.
The part of the human respiratory system where gas exchange occurs is the
The alveoli are the site of gas exchange, where oxygen diffuses into the blood and carbon dioxide is removed.
In a plant species, the closure of stomata during the day is regulated by which of the following physiological responses to water stress?
Abscisic acid (ABA) accumulates under water stress, signaling guard cells to close stomata by reducing turgor pressure, thus minimizing water loss.
The hormone that stimulates the contraction of the uterus during childbirth is
Oxytocin, released by the pituitary gland, triggers uterine contractions during labor.
In a freshwater ecosystem, the introduction of an invasive species is most likely to result in
Invasive species often outcompete native species, disrupting trophic interactions and potentially leading to the decline of native populations.
In a population of plants, the frequency of a recessive allele (b) for flower color is 0.4. What is the frequency of individuals with the dominant phenotype (BB or Bb)?
If q = 0.4 (b), then p = 0.6 (B). The frequency of the dominant phenotype (BB + Bb) is p² + 2pq = (0.6)² + 2(0.6)(0.4) = 0.36 + 0.48 = 0.84.
Which of the following adaptations in a deep-sea fish allows it to survive under high pressure?
Deep-sea fish have flexible, fluid-filled bodies that equalize internal and external pressure, preventing collapse under high-pressure conditions.
In a plant species, the rate of nitrogen fixation decreases under anaerobic conditions. What is the most likely explanation for this observation?
Nitrogenase, the enzyme responsible for nitrogen fixation, is oxygen-sensitive; anaerobic conditions reduce its activity, decreasing nitrogen fixation in root nodules.
In a population of birds, the introduction of a new predator leads to the survival of individuals with longer beaks. This is an example of
Directional selection favors longer beaks, shifting the population's beak length distribution as they provide an advantage against the new predator.
In a plant species, the rate of water uptake decreases under saline conditions. What is the most likely explanation for this observation?
Saline conditions lower the soil's water potential, making it harder for roots to absorb water due to the osmotic gradient, reducing water uptake.
What type of nutrition do green plants exhibit when they produce their own food?
Green plants are autotrophic, meaning they produce their own food through photosynthesis using sunlight, water, and carbon dioxide.
Which of the following is a renewable resource in an ecosystem?
Timber is a renewable resource because trees can be replanted and regrown, unlike coal, petroleum, and natural gas, which are non-renewable.
Which of the following is a characteristic of a desert ecosystem?
Deserts are characterized by low rainfall, making them arid environments with sparse vegetation.
Which of the following is a characteristic of a virus?
Viruses cannot reproduce on their own and require a host cell to replicate, using the host's machinery.
Which of the following is a characteristic of a savanna ecosystem?
Savannas are grasslands with scattered trees, typically found in warm regions with distinct wet and dry seasons.
What is the primary role of the brain in the human body?
The brain controls body activities, including movement, thoughts, and regulation of vital functions like breathing.
Which of the following animals is an example of a carnivore?
A tiger is a carnivore, feeding primarily on meat, unlike goats, elephants, and squirrels, which are herbivores or omnivores.
What is the primary role of the stomach in the human digestive system?
The stomach breaks down food using enzymes and acid, starting the digestion of proteins.
Which of the following structures in a plant cell provides support and protection?
The cell wall, made of cellulose, provides support and protection to plant cells, maintaining their shape.
What is the term for an organism that breaks down dead matter to recycle nutrients?
Decomposers, like bacteria and fungi, break down dead matter, recycling nutrients back into the ecosystem.
Which of the following is a characteristic of a bird?
Birds are characterized by feathers, which help with flight, insulation, and camouflage.
What is the primary role of the diaphragm in the human respiratory system?
The diaphragm is a muscle that contracts and relaxes to help the lungs expand and contract during breathing.
Which of the following animals is a mammal?
Dolphins are mammals, characterized by traits like nursing their young with milk and breathing air.
What is the primary function of the adrenal glands in the human body?
The adrenal glands produce stress hormones like adrenaline, which help the body respond to stress.
Which of the following is a characteristic of a tundra ecosystem?
Tundra ecosystems are characterized by cold temperatures, low biodiversity, and a short growing season.
What is the term for the relationship where one organism benefits and the other is unaffected?
Commensalism is a relationship where one organism benefits while the other is neither harmed nor benefited, like a bird nesting in a tree.
Which of the following animals is an example of a reptile?
Lizards are reptiles, characterized by dry, scaly skin and laying eggs on land.
What is the primary role of the spleen in the human body?
The spleen filters blood, removing old red blood cells and helping the immune system by storing white blood cells.
What is the term for the process by which a plant bends towards light?
Phototropism is the growth response of a plant towards light, helping it maximize photosynthesis.
The primary role of enzymes in living organisms is to
Enzymes are biological catalysts that speed up biochemical reactions by lowering the activation energy, without being consumed in the process.
In a cross between two heterozygous tall pea plants (Tt), what is the probability of producing a homozygous recessive (tt) offspring?
In a Tt x Tt cross, the Punnett square shows 25% TT, 50% Tt, and 25% tt. Thus, the probability of a homozygous recessive (tt) offspring is 25%.
The process by which a barren landscape develops into a stable ecosystem over time is called
Ecological succession is the gradual process by which ecosystems develop and change over time, starting from a barren landscape to a stable climax community.
The primary organ responsible for filtering waste products from the blood in humans is the
The kidneys filter waste products like urea from the blood, forming urine, which is excreted from the body.
The process by which organisms with favorable traits survive and reproduce more successfully is called
Natural selection is the process where organisms with traits better suited to their environment survive and reproduce, passing those traits to offspring.
Now practice in exam mode
You've studied the answers — now test yourself under real exam conditions with the timer running.
Start JAMB Biology 2001 Quiz