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:
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:
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:
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:
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:
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 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:
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 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:
Asteroids from space, which contained ice, arrived on Earth. This is the most accepted theory for the origin of water on Earth. This theory, often referred to as the "Late Heavy Bombardment" theory, suggests that during the early stages of the Solar System's formation, a significant number of asteroids and comets, some of which contained water in the form of ice, bombarded the Earth. Over time, as these icy bodies collided with Earth, they contributed to the accumulation of water on the planet's surface. Choice A is correct.

Choice B is incorrect, as water was present on Earth before early organisms were present. Choice C is incorrect because free oxygen atoms were absent in the early atmosphere. Choice D is incorrect because liquid water would need to be present on Earth before it could be converted into steam.

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

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:
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:
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:
All three statements are correct. The first part of the binomial name is the genus, the second part is the species which is unique to platypus species. The binomial system and binomial names are agreed between biologists at international congresses.

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:
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:
Choice D is correct. The DNA sequence (Statement I) and amino acid sequence (Statement II) are the usual, present way of determining members of the same clade, however, physical appearance (Statement III) was previously, but is now rarely, used.

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 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:
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:
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:
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:
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).