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:
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 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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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 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:
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 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:
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:
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 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:
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:
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:
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:
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.