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:
All 64 codons of the genetic code are present in all organisms, apart from minor variations indicating that all life evolved from the same original cells (Choice D).

Eukaryotic cells evolved from prokaryotic cells (Choice A) is incorrect as this is the endosymbiotic theory. Choice B is incorrect as mitochondria do not have a cell wall. Choice C is incorrect as bacteria do not have histones.

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:
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:
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:
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:
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:
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:
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.

Explanation:
Species that share a recent common ancestor, such as humans and chimpanzees, are more likely to have similar base sequences. Over time, as species diverge and evolve, mutations accumulate in their base sequences. The longer two species have been separated from their common ancestor, the more mutations will have accumulated in their genomes. Therefore, species that are closely related have fewer accumulated mutations and more similar base sequences (Choice B).

Choice A is incorrect because genome size is not necessarily proportional to the size of the species. The genome size can vary significantly even among organisms of similar size, and organisms with similar-sized genomes, such as the horse and mouse vary greatly in size. Choice C is incorrect because it is possible to have a larger genome size with a comparable, or even smaller, number of genes, depending on the amount of non-coding DNA and repetitive sequences present in the genome. Humans have a larger genome but a similar number of genes to the chimpanzee, mouse and horse. Choice D is incorrect because although the nucleotide base sequence in the table for humans and chimpanzees is the same it does not mean that their whole genome is the same.

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:
The chromosomes of eukaryotes are linear, and the DNA is coiled around histone proteins (Choice C). Choice A is incorrect because eukaryotic DNA molecules are not circular. Choice B is incorrect because eukaryotic cells do not have looped DNA in the nucleus. Choice D is incorrect because the linear DNA molecules in eukaryotic cells are coiled around histone proteins.

Explanation:
Choice B is not true. Not all genes are expressed in each cell. Only the necessary genes are expressed based on the specialised function of the cell. All other statements are true.

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:
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:

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:
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:
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:
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:
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:
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:
A group of individuals living in a defined area is not a biological definition (Choice A). A group of individuals of the same species living in a given area at the same time who are interacting with each other is a population (Choice B) and the environment in which they live is a habitat (Choice C). It is only when they can interbreed to produce fertile offspring that they can be considered a species. (Choice D).

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 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).