Explanation​:
Choice B is the correct definition for a clade, a group of organisms that share a common ancestor. Choice A and C are incorrect as they do not feature the idea of a common ancestor. Choice D is incorrect because organisms within a clade do share a common ancestor.

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​:
Louis Pasteur's experiments where he boiled nutrient broth in swan-necked flasks disproved spontaneous generation. Choice B is correct.

Miller and Urey's (Choice A) experiments proved that organic compounds could be produced in Earth’s early atmosphere. Rosalind Franklin’s (Choice C) work was instrumental in the discovery of the structure of DNA. Meselson and Stahl (Choice D) proved that DNA replication is semi-conservative.

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​:
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 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​:
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​:
Prokaryotic cells do not contain mitochondria but eukaryotic cells do. Choice D is correct.

Choice A is incorrect as eukaryotes (as well as Archae) contain 80S ribosomes. Choice B is incorrect as both eukaryotic and prokaryotic cells contain a plasma membrane. Choice C is incorrect as eukaryotic cells contain a nucleus but prokaryotic cells do not.

Explanation​:
Choice A is correct because the hierarchy of taxa is a domain, kingdom, phylum, class, order, family, genus, so class $\to$ order $\to$ family is in the correct order. Choice B is incorrect because the class is above order. Choice C is incorrect because the family is above genus. Choice D is incorrect because the phylum is above order.

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​:
Unlike eukaryotes, prokaryotes lack a nucleus and membrane-bound organelles. However, like eukaryotes, prokaryotes contain ribosomes, a non-membrane-bound organelle required for protein synthesis. So, ribosomes are found in both prokaryotes and eukaryotes.

Lysosomes (Choice A) and the Golgi apparatus (Choice C) are only found in eukaryotes. The nucleoid (Choice D) is only found in prokaryotes.

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​:
Choice A is correct because statements I and II are common features of bacterial cells. Archaeans, which are prokaryotes, have DNA associated with histone proteins, but bacteria do not (statement III).

Explanation​:

Rewilding projects attempt to restore and rehabilitate ecosystems by reintroducing native species and allowing natural processes to become re-established. Statement I is therefore correct. Recycling and reusing products means fewer resources will be extracted from the Earth which is a process that can destroy natural habitats and lead to excessive landfill use, so Statement II is correct. Choice C is therefore correct (Statement I and II).

Increasing meat consumption (Statement III) results in more land being cleared for animals such as cattle to be bred, decreasing biodiversity. Choice D is therefore incorrect as it includes this statement. Choices A and B are missing one of the possible solutions to the crisis and are therefore incorrect.

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:
Choice A is correct because Chargaff used paper chromatography to show that the proportions of adenine (A) and thymine (T) are the same, as are the proportions of guanine (G) and cytosine (C). There are not equal proportions of A, T, G and C.

Franklin (Choice B) and Watson (Choice D) are credited for their contributions to the overall structure of DNA structure. Hershey (Choice C), along with Chase, is famous for his research which provided evidence for the idea that DNA, rather than protein, carries the genetic code.

Explanation​:
The number of organisms found via the fossil record for any era is much lower compared to the number of organisms found on Earth now and those that continue to be found, so Choice B is correct. Choice A is incorrect as changing levels of atmospheric carbon dioxide provide evidence for humans' impact on carbon dioxide levels. Choices C and D are incorrect as evidence suggests that the rate of evolution and speciation are increasing, which provides evidence for increasing biodiversity.

Explanation:
Evolution is the change in the characteristics of a population over time; these characteristics can be passed from one generation to another (Choice A). Choice B is incorrect as it describes when organisms are reproductively isolated, which is a mechanism that may lead to evolution in a population. Choice C is incorrect because it refers to learned behaviours which are learned within an organism’s lifetime and are not genetically inherited. Choice D is incorrect as it refers to selective breeding.

Explanation​:
The nucleotide strand CCUAGAGCUUACCG contains the bases cytosine (C), uracil (U), adenine (A), and guanine (G). While C, A, and G are found in both DNA and RNA, the base uracil is only found in RNA. So, the strand is an RNA strand.

RNA contains the pentose sugar ribose. Therefore, ribose is found in the nucleotides in the strand.

Choices A and C are incorrect because deoxyribose is only found in DNA, not RNA. The nucleotide strand cannot be DNA because it contains uracil in place of thymine (T).

Choice D is incorrect because the strand is RNA which contains ribose.

Explanation​:
Choice A - Excretion is the process wherein waste and excess water in the organism are removed. Paramecia expel waste products such as carbon dioxide through the process of diffusion.

Choice B - Homeostasis pertains to the ability of living things to maintain a stable internal environment. Paramecia maintain a stable internal condition by expelling excess water using the contractile vacuole.

Choice C - Reproduction is the biological process by which organisms produce offspring that are biologically similar to themselves. Paramecia can reproduce sexually through meiosis and asexually through mitosis.

Choice D - Metabolism refers to all the chemical reactions in organisms such as anabolic and catabolic reactions. Paramecia produce enzymes that catalyse different catabolic and anabolic reactions in the cell.

Explanation:
Choice D is correct because water has a relatively high density compared to many substances which increases the buoyancy forces it exerts on objects submerged in it.

Choice B is incorrect because specific heat capacity refers to how much energy is required to raise the temperature of a unit of mass of a given substance by one degree Celsius. Choice C is incorrect because viscosity refers to the resistance of a fluid to an object moving through it or to flow of the fluid itself.

Explanation:
DNA molecules consist of four nitrogenous bases: adenine (A), cytosine (C), guanine (G) and thymine (T). In DNA molecules, adenine always pairs with thymine and cytosine always pairs with guanine. This is known as complementary base pairing.

Sequences I and III both follow base-pairing rules correctly. Statement II is incorrect because it shows T paired with G and A paired with C.

Explanation​:
Cholesterol (Choice C) is a non-polar hydrophobic molecule. Therefore, it is insoluble in water.
Glucose (Choice A), amino acids (Choice B), and sodium chloride (Choice D) are soluble in water and are hydrophilic.

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.