Explanation​:
Ribosomes carry out protein synthesis, not the Golgi apparatus. Choice A is correct. Choices B, C and D are incorrect as they are all functions of the Golgi apparatus.

Explanation​:
Choice A is correct because Eukaryota are the only group with nuclei and membrane-bound organelles. Choice B and choice C are incorrect because organisms in these two domains (Archaea and Eubacteria) do not have membrane-enclosed organelles. Choice D is incorrect because prokaryotes are not the name of a domain.

Explanation​:
DNA molecule is made up of two antiparallel strands of nucleotides. Antiparallel means that both strands are geometrically parallel but oriented in opposite directions (Option II). One of the strands is in the direction of 5' to 3', whereas the other strand is in the direction of 3' to 5'. The backbones, made of alternating sugar and phosphate groups, are held together by covalent phosphodiester bonds (Option III). Both of these strands are joined together by the hydrogen bonds between the complementary base pairs.

DNA strands are not symmetrical (Option I) because symmetrical would mean that they are a mirror image of each other.

Explanation​:
Choice D is correct because organisms placed in the same group share common ancestry. Choice A and Choice B are incorrect because morphology and anatomical characteristics are used to describe the structures of organisms which are used to primarily group them together. Choice C is incorrect because modes of nutrition are used to describe organisms but not to classify organisms.

Explanation​:
Gravity is responsible for holding water on Earth and is a fundamental factor in water retention within the planet's atmosphere and surface. Choice D is, therefore, correct.

Choice A is incorrect, as although rainfall is a part of the water cycle and is responsible for distributing water, it does not directly contribute to the retention of water on Earth.

Choice B is incorrect, as the moon's gravitational force regulates the tides of large bodies of water but does not directly contribute to water retention on Earth. Choice C is incorrect as water is lost from bodies of water on the surface of the Earth and evaporates into the atmosphere, which doesn't directly address water retention.

Explanation​:
Polyploidy is when an organism develops a mutation where they have more than two sets of the haploid number of chromosomes. Choice B is correct as it has 8 sets of 3 chromosomes.

Choice A is incorrect, as it is the diploid number, which is double the haploid number. Choice C is incorrect, as it is the haploid number of chromosomes. Choice D is incorrect because it is not a multiple of the haploid number.

Explanation:
Hydrophilic (Choice C) substances dissolve in water through the formation of hydrogen bonds with water.
Non-polar (Choice D) substances are not attracted to water molecules and do not form bonds with them. These substances are hydrophobic (Choice B), making them insoluble (Choice A) in water.

Explanation:
The resolution is the ability to distinguish between two objects. Choice B is correct.

Choices A and D are incorrect because a photograph taken using an electron microscope would allow the ultrastructure of the cells (fine detail of cells, such as organelles) to be observed. Choice C is incorrect because these photographs are magnified at the same power.

Explanation​:
Choices A, B and D are incorrect as they all have a single membrane.

Explanation:
Bound ribosomes synthesise proteins for secretion outside of the cell, membrane-associated proteins or proteins used in lysosomes (Choice D).

Choice A is incorrect, as free ribosomes synthesise proteins for use primarily within the cytoplasm.
Choice B is incorrect as bound ribosomes do not transport mRNA from the nucleus to the cytoplasm.
Choice C is incorrect as ribosomes do not destroy proteins.

Explanation​:
Nucleotides are linked together by condensation reactions to form molecules of DNA (Choice B). The formation of DNA requires the removal of water for the joining of smaller molecules to form a larger molecule.

The joining of nucleotides together can also be classified as an anabolic reaction but not as a catabolic reaction (Choice C). Catabolism is the breaking down of a large molecule into a smaller molecule. An example of catabolism is hydrolysis which is a reaction that breaks down a large molecule into a smaller molecule by adding water (Choice A).

Translation is a process which follows the transcription of DNA (Choice D). It is where mRNA is used as a template by ribosomes to synthesize polypeptides.

Explanation​:
RNA is believed to be a potential candidate for the first genetic material due to its ability to form spontaneously from nucleotides (Statement I). Miller's famous experiment demonstrated that simple organic molecules, including nucleotides, could be produced from a mixture of gases under conditions that simulated early Earth (Statement III). This experiment suggested that nucleotides could have formed spontaneously on a prebiotic Earth, providing a plausible scenario for the emergence of RNA as the first genetic material. Therefore Choice B is correct.

Choice A only included Statement I and not II, so it is incorrect. While it is true that RNA contains ribose as its sugar component (Statement II), the presence of ribose is not a primary reason for RNA being considered the first genetic material. Both RNA and DNA contain sugars in their structures, but the key point in favour of RNA as the first genetic material is its ability to form spontaneously. Choices C and D included Statement II and so are incorrect.

Explanation:
Adhesive properties (Choice B) refer to water’s ability to stick to charged surfaces or polar molecules. This, together with cohesion, allows water to move against gravity up the stem through capillary action.

Water's melting point (Choice A) is the temperature at which it changes its state from solid to liquid.

The specific heat capacity (Choice C) of water pertains to the amount of heat energy needed to raise its temperature by 1 °C.

The buoyant force of water (Choice D) is the upward force on an object submerged or partially immersed in water, equal to the weight of the displaced water.

Explanation​:
Choice B is correct because X labels the core histone proteins which help package the DNA into nucleosomes through coiling.

Choice A is incorrect because X is not linker DNA which extends from one nucleosome to the next, connecting nucleosomes with one another. Choice C is incorrect because enzymes carry out DNA replication, not histone proteins. Choice D is incorrect because DNA carries genetic material, not the core histone proteins.

Explanation:
Organelles of a eukaryotic cell are enclosed by a single or double membrane. Double membrane-bound organelles include the nucleus, mitochondria, and chloroplasts. So, a mitochondrion has a double membrane.

The Golgi apparatus (Choice A), lysosome (Choice C), and endoplasmic reticulum (Choice D) all have a single membrane.

Explanation:
X is pointing to the nucleus and Y is pointing to a mitochondrion. Choice A is incorrect as neither organelle has a single membrane. Choice B is incorrect as only mitochondria contain cristae, the nucleus does not. Choice D is incorrect as neither the nucleus or mitochondria contain starch grains.

Explanation​:
Choice D is correct because homologous structures refer to structures inherited from a common ancestor which are similar but often used for different functions.

Choice A is incorrect, as ancestral structures refer to structures present in an ancestor species, not structures found in present day species. Choice B is incorrect as convergent structures are not a term used in biology. Convergent evolution, on the other hand, leads to analogous structures. Choice C is incorrect as analogous structures refer to structures used for the same function, which are significantly different when closely inspected. Analogous structures also have different evolutionary origins.

Explanation:
Statement I is true because all cells have cytoplasm enclosed by the plasma membrane.

Statement II is also true because the invention of the microscope made viewing structures within the cell easier.

Statement III is false because all cells have genetic material. Eukaryotic cells have their genetic material inside of the nucleus, while prokaryotes have their genetic material in the nucleoid region.

Explanation​:
Isotopes with long half-lives (Choice C), such as uranium and potassium isotopes, are often used in absolute dating because they decay slowly and are suitable for dating older fossils.

Stable isotopes (Choice A) are not used for fossil dating because they do not undergo radioactive decay. Absolute dating relies on the measurement of the decay of radioactive isotopes into stable daughter isotopes to determine the age of a sample. Isotopes with short half-lives (Choice B) are typically used for dating more recent events, not older fossils. Isotopes with no half-lives (Choice D) cannot be used for fossil dating using the methods based on radioactive decay. Isotopes without half-lives do not undergo radioactive decay, so it is impossible to establish a chronology or estimate the age of a fossil using these isotopes.

Explanation​:
The endosymbiotic theory states that larger prokaryotes engulfed smaller prokaryotes, which were the ancestors of modern chloroplasts and mitochondria, eventually evolving into eukaryotes. Choice A is correct.

Statement I (Choices B and D) is incorrect as prokaryotes were not formed by the endosymbiotic theory. Statement III (Choice C) is incorrect as spontaneous generation is impossible.

Explanation:
Water's thermal properties (Choice A) include a high heat of vaporisation which results in the absorption of a large amount of heat by water before changing its physical state. This means that changing the temperature of the water is slow, and this helps to maintain the internal temperature of organisms between set limits.
Water has cohesive properties (Choice B) which means it sticks to other water molecules.
Water has adhesive properties (Choice C) which means it adheres to charged surfaces.
Water is an excellent solvent (Choice D) which means it dissolves a wide array of polar and ionic substances.

Explanation​:
Uracil and thymine are nitrogenous bases found in two types of nucleic acids: DNA and RNA.

Uracil is found in RNA, whereas thymine is found in DNA. (Choice B)

Uracil pairs with adenine in RNA and thymine pairs with adenine in DNA (Choice D).

In both DNA and RNA, these nitrogenous bases are joined to a five-carbon sugar, also called a pentose sugar which has a ring structure, so Choice A is incorrect.

Both uracil and thymine are pyrimidines which are single-ring structures (Choice C). Adenine and guanine are purines which consist of two rings.

Explanation​:
Choice D is correct because the three domains of organisms are Archaea, Eubacteria and Eukaryota. Choice A is incorrect because prokaryote is not the name of one of the domains. Choice B is incorrect because Protista and prokaryota are not the names of domains. Choice C is incorrect because Protista is not one of the domains.

Explanation:
Choice B is correct because two reproductively isolated populations are a key component of the definition of a species.

Choice A is incorrect because allele frequencies often differ between different populations of the same species. Choice C is incorrect because varying DNA sequences in genes confirms the existence of different alleles, not the existence of two species. Choice D is incorrect because even when two populations are geographically isolated, they may still be the same species.

Explanation​:
Vesicles are formed from a phospholipid bilayer. This phospholipid bilayer forms spontaneously because the phosphate heads are hydrophilic (‘water loving’), and the fatty acid tails are hydrophobic (‘water hating’). Therefore Choice B is correct.

The membrane around the vesicle is not a single layer (Choices A and C) of phospholipids due to the hydrophilic phosphate heads naturally pointing outwards and inwards into the aqueous environments, and the hydrophobic fatty acid tails aligning in the centre to minimise their exposure to water. Vesicles are not induced to form in cells (Choices C and D) as the amphipathic nature of the phospholipids means that the vesicles form through self-assembly.