28 reviewed questions with answers and explanations.
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The cytoplasm of the cell is considered a very important component because it
B: suspends cytoplasmic organelles
Cytoplasmic organelles are suspended within the cytoplasm. The cell membrane forms the outer boundary, and cell division involves several coordinated cellular structures.
AI-reviewed · source checkedWith a membrane permeable to water but not sugar, the liquid level in the thistle funnel will initially
The illustrated experiment with a selectively permeable membrane demonstrates
Red blood cells burst after being placed in distilled water. This rupture is called
C: haemolysis
Red blood cells take up water in a strongly hypotonic solution such as distilled water. If they rupture, the breakdown of the red cells is called haemolysis.
AI-reviewed · source checkedThe curvature movement of plants in response to the stimulus of water is called
A: hydrotropism
Hydrotropism is directional plant growth in response to a water gradient. Roots can grow toward wetter conditions, helping the plant obtain water.
AI-reviewed · source checkedThe longest bone in the adult human body is the
B: femur
The femur, or thigh bone, is the longest bone in the normal adult human skeleton. It extends between the hip and knee and supports substantial body weight.
AI-reviewed · source checkedWhich of the following structures is not a skeletal material?
D: Muscle
Bone and cartilage form supporting skeletal tissues in vertebrates, while chitin contributes to many arthropod exoskeletons. Muscle contracts to move supporting structures.
AI-reviewed · source checkedThe slow flow of blood through capillary beds is useful because it helps
D: to allow adequate time for exchange of materials
Slow capillary flow gives more time for exchange of gases, nutrients and wastes across vessel walls. The large total cross-sectional area of capillary beds helps produce that low velocity.
AI-reviewed · source checkedWhich of the following groups of organisms has kidney as their excretory organ?
A: Fishes, amphibians, birds, man
Fishes, amphibians, birds and humans are vertebrates that use kidneys for excretion and water–salt regulation. The other groups include organisms with different excretory structures.
AI-reviewed · source checkedWhich is NOT a characteristic of arteries in the adult mammalian circulation? Arteries
A: possess valves at intervals throughout their length
Arteries carry blood away from the heart and have walls suited to pressure. They do not have repeated valves along their length like many limb veins.
AI-reviewed · source checkedWhich statement is supported by the temperature graph?
Which term describes the substantial variation in the lizard body temperature shown?
Compared with plain water, an appropriately formulated isotonic saline infusion helps
C: to maintain the composition of body fluids
An appropriately formulated isotonic saline solution helps preserve extracellular osmotic conditions. Plain water introduced into the circulation can cause harmful osmotic shifts in blood cells.
AI-reviewed · source checkedThe part of the inner ear containing sensory hair cells for hearing is the
A: cochlea
The cochlea contains the organ of Corti, whose sensory hair cells respond to mechanical vibrations. They convert movement into signals transmitted through auditory nerve fibres.
AI-reviewed · source checkedSpectacles with convex lenses correct long-sightedness by
A: converging the Light rays before they enter the eye
A convex lens adds convergence to incoming light. In a long-sighted eye this helps bring the focus forward onto the retina rather than behind it.
AI-reviewed · source checkedWhich of the following processes removes carbon from the atmosphere?
B: Photosynthesis
Photosynthesis takes carbon dioxide from the surroundings and incorporates its carbon into organic compounds. Combustion and decomposition generally release carbon dioxide instead.
AI-reviewed · source checkedWhich of the following cycles involves the process of precipitation and transpiration?
A: Water cycles
Precipitation returns atmospheric water to the surface, while transpiration releases water vapour from plants. Both are transfers within the water cycle.
AI-reviewed · source checkedWhat is the critical limiting factor for plants below the photic zone in an aquatic ecosystem?
C: intensity of light
Below the photic zone, insufficient light limits photosynthesis. Water may be abundant, but photosynthetic organisms still need enough usable light energy.
AI-reviewed · source checkedWhich instrument is used in sampling to estimate the number of plants in a habitat?
C: Quadrat
A quadrat defines a known sample area in which plants can be counted. Representative repeated samples can then estimate abundance across a habitat.
AI-reviewed · source checkedWhich of the following statements is true about sandy soil? It
B: is light and easy to dig
Sandy soil is generally relatively loose and easy to work. Its large pores commonly promote drainage and aeration, though organic matter and compaction can modify its behaviour.
AI-reviewed · source checkedWhich organism is a primary consumer when feeding on grass?
B: Sheep
A sheep feeding on plants is a primary consumer because it obtains energy directly from producers. Grass is a producer, while fungi commonly act as decomposers.
AI-reviewed · source checkedIn the food chain P → Q → R → S → T, P is a photosynthetic producer. Its initial energy source is
A: sunlight
In a grazing food chain beginning with a photosynthetic producer, sunlight supplies the initial energy. The producer converts some light energy into chemical energy passed along the chain.
AI-reviewed · source checkedIn P → Q → R → S → T, with P a producer and arrows showing energy flow, R
D: is a secondary consumer
P is the producer and Q is the primary consumer. R feeds on Q, so R occupies the secondary-consumer level in this chain.
AI-reviewed · source checkedWhich condition is caused by a mite infestation rather than an inherited gene variant?
B: Scabies
Scabies is caused by infestation with the human itch mite. It is acquired through transmission of mites rather than inherited as a genetic condition.
AI-reviewed · source checkedDNA in eukaryotic cells is contained in the
B: nucleus
The nucleus contains most of the DNA in a typical eukaryotic cell, organised into chromosomes. Mitochondria and chloroplasts can also contain DNA.
AI-reviewed · source checkedCytokinesis accompanying mitosis divides the cytoplasm so that
A: daughter cells receive cytoplasm and organelles
Cytokinesis divides the cytoplasm between daughter cells, distributing cytoplasmic contents and organelles. Chromosome segregation occurs during nuclear division.
AI-reviewed · source checkedWhich method can compare biological material from a crime scene with a reference sample to help identify its source?
B: DNA analysis
DNA profiling compares genetic markers in biological samples. It can support identification when samples and statistical interpretation are reliable, but is one component of an investigation.
AI-reviewed · source checkedThe independently evolved similarity in swimming function and external form of whale flippers and fish fins illustrates
D: convergent evolution
The swimming surfaces of whale flippers and fish fins show functional similarity associated with life in water. Such independently evolved similarities are examples of convergence.
AI-reviewed · source checked