28 reviewed questions with answers and explanations.
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Which plant tissue contains actively dividing, relatively undifferentiated cells?
A: Meristem
Meristematic tissue consists of relatively undifferentiated cells that divide to produce new plant tissues. Its cells remain capable of active growth, unlike the more specialised tissues listed.
AI-reviewed · source checkedAnnelids differ from nematodes in that they
C: are metamerically segmented
Annelids have repeated body segments, a condition called metameric segmentation. Nematodes are unsegmented roundworms, although they share other general features such as bilateral symmetry and three germ layers.
AI-reviewed · source checkedWhich of the following perform similar functions?
D: Strobili and inflorescence
Strobili group reproductive structures on an axis, while an inflorescence groups flowers. Both organise reproductive units together, even though their component structures and the plants that bear them differ.
AI-reviewed · source checkedIn ferns, the mature sporophyte
D: is diploid and independent of the gametophyte
The mature fern sporophyte is diploid and can live independently. It produces haploid spores by meiosis. The young sporophyte initially develops on the gametophyte before becoming an independent fern.
AI-reviewed · source checkedThe group of insects that undergoes complete metamorphosis is
C: houseflies, beetles and butterflies
Houseflies, beetles and butterflies pass through egg, larva, pupa and adult stages. The distinct pupal stage is a feature of complete metamorphosis, unlike the nymphal development of cockroaches and grasshoppers.
AI-reviewed · source checkedThe nitrogenous substance that is excreted by birds in order to conserve water is
C: uric acid
Birds eliminate much of their nitrogenous waste as uric acid and urates. These can be excreted with relatively little water, helping conserve water compared with eliminating large amounts of dissolved ammonia.
AI-reviewed · source checkedWhich sphincter is located where the gullet enters the stomach?
B: cardiac sphincter
The cardiac, or lower oesophageal, sphincter is at the junction where the gullet enters the stomach. The pyloric sphincter is at the other end, where stomach contents pass toward the duodenum.
AI-reviewed · source checkedOozing out of water from the leaves of plants in a humid environment is known as
D: guttation
Guttation is the release of liquid water from leaf edges or tips, usually through hydathodes. It can occur when root pressure is relatively high and transpiration is low, as in humid conditions.
AI-reviewed · source checkedThe element that is essential for the coagulation of blood is
B: calcium
Calcium ions are required at several stages of the blood-clotting cascade. They help the clotting reactions proceed toward fibrin formation, alongside clotting proteins and platelet-related processes.
AI-reviewed · source checkedCompared with aerobic respiration of glucose, alcoholic fermentation in yeast produces
C: a smaller amount of usable energy and alcohol
Alcoholic fermentation in yeast yields ethanol and much less usable energy per glucose than aerobic respiration. Only the small ATP yield of glycolysis is obtained, while fermentation regenerates NAD+ for glycolysis to continue.
AI-reviewed · source checkedThe process of deamination is essential for the
C: formation of urea
Deamination removes nitrogen-containing amino groups from amino acids. In mammals, the resulting nitrogen can be incorporated into urea for excretion, preventing toxic ammonia from accumulating.
AI-reviewed · source checkedThe appendicular skeleton consists of the pectoral girdle together with the
A: pelvic girdle, forelimbs and hindlimbs
The appendicular skeleton includes the limb girdles and the limbs they support. Together, the pectoral girdle, pelvic girdle, forelimbs and hindlimbs form this division of the skeleton.
AI-reviewed · source checkedThe companion cells are part of the
B: phloem
Companion cells are associated with sieve-tube elements in angiosperm phloem. They provide metabolic support and participate in loading and unloading substances transported through the phloem.
AI-reviewed · source checkedWhich form of vegetative reproduction is illustrated?
Coconut and oil palm fruits can be grouped as
D: drupe
Coconut and oil-palm fruits are drupes. Each has a fruit wall differentiated into layers, including a hard inner layer around the seed; coconut also has a conspicuously fibrous outer portion.
AI-reviewed · source checkedThe substance that is responsible for apical dominance in plants is known as
C: auxin
Auxin produced near the shoot tip contributes to apical dominance, helping suppress the growth of lateral buds. Removing the tip changes hormonal interactions and can allow side shoots to grow.
AI-reviewed · source checkedThe ability of the eye to focus on both near and distant objects is termed
D: accommodation
Accommodation is adjustment of the eye’s optical power to focus objects at different distances. Changes in lens curvature help bring light from nearby or distant objects into focus on the retina.
AI-reviewed · source checkedThe speed of wind can be measured with an instrument called
C: anemometer
An anemometer measures wind speed. A wind vane indicates wind direction instead. The other instruments listed measure properties of liquids or underwater visibility rather than wind movement.
AI-reviewed · source checkedIn a food web, arrows run from food to consumer: corn → weevils; corn → grasshopper; rice → weevils; rice → rat; rice → grasshopper; weevils → rat; rat → hawk; grasshopper → hawk; grasshopper → praying mantis; praying mantis → hawk. Which listed organism is an omnivore?
B: Rat
The rat receives food from rice and from weevils in the represented web. Eating both plant and animal material makes it an omnivore. The other listed consumers have only plant or only animal food links here.
AI-reviewed · source checkedToads and lizards in an ecosystem depend on a limited quantity of food. This is an example of
D: interspecific competition
Competition for a limited shared food supply between different species is interspecific competition. Toads and lizards are different groups, so the interaction is not competition within one species.
AI-reviewed · source checkedThe Southern Guinea Savanna differs from the Northern Guinea Savanna in that it has
C: more rainfall and taller grasses
The Southern Guinea Savanna generally has a wetter climate and taller grass vegetation than the Northern Guinea Savanna. The regional pattern reflects the south-to-north gradient toward drier conditions.
AI-reviewed · source checkedIn a soil sample, the relative amounts of the different soil particles can best be determined by the process of
D: sedimentation
Sedimentation separates suspended soil particles by differences in settling behaviour. Under controlled conditions, measurements at suitable times help estimate sand, silt and clay fractions and therefore soil texture.
AI-reviewed · source checkedWhich measure directly prevents Guinea worm exposure through unsafe drinking water?
D: provision of potable drinking water
Access to safe drinking water prevents people from swallowing infected copepods, a major route of Guinea worm transmission. Education and surveillance also help, but protected water supply directly addresses this exposure.
AI-reviewed · source checkedDuring binary fission in a typical unicellular eukaryote, the nucleus divides by
A: mitosis
In a typical unicellular eukaryote reproducing by binary fission, mitosis separates duplicated nuclear chromosomes before the cell divides. This usually preserves the chromosome complement in the daughter cells.
AI-reviewed · source checkedOne reason for the success of Mendel’s work is that he
B: introduced quantitative and qualitative elements into his work
Mendel carefully distinguished contrasting traits and counted their occurrence in offspring. Combining controlled crosses with numerical results allowed him to recognise regular inheritance ratios.
AI-reviewed · source checkedBoth parents have sickle cell trait, with genotype HbA/HbS. What is the probability that a child has genotype HbA/HbA?
B: ¼
Each HbA/HbS parent can contribute HbA or HbS. The four equally likely combinations are HbA/HbA, HbA/HbS, HbS/HbA and HbS/HbS. Only one has no HbS allele, giving a probability of one quarter for each pregnancy.
AI-reviewed · calculation checkedThe three broad caste categories in a termite colony are
B: workers, soldiers and reproductives
The main termite caste categories are workers, soldiers and reproductives. The reproductive category includes the king and queen, so it covers roles omitted when only one royal sex is listed.
AI-reviewed · source checkedFossil records found in sedimentary rocks offer some explanation for the theory of evolution because
A: the deposits have remains of organisms characteristic of when they were formed
Fossils in sedimentary deposits can record organisms that lived during the period when those deposits formed. Comparing fossil assemblages through successive layers provides evidence of biological change over time.
AI-reviewed · source checked