Explanation:
Choice D is correct because food is stored in the cotyledon(s). Choice A is incorrect because the function of the radicle is to develop into the root of the seedling. Choice B is incorrect because the function of the plumule is to develop into the shoot of the seedling. Choice C is incorrect because the testa is the outer covering of the seed.

Explanation:
Choice C is correct because the transfer of seeds away from the parent plant is dispersal. Choice A is incorrect because the fusion of a male and female gamete is fertilization. Choice B is incorrect because the transfer of pollen from an anther to a stigma is pollination. Choice D is incorrect because pollen transfer involves the movement of pollen, not seeds.

Explanation:
The largest area in the pie charts showing sources of methane and nitrogen oxides is agricultural production.

Land use and biomass burning (Choice A) are a source of both methane and nitrous oxide but the area in the pie charts is less than agricultural production.

Industrial use (Choice B) releases mainly nitrous oxide.

Residential sources (Choice C) also release both methane and nitrous oxide but in lesser amounts than agricultural production.

Explanation:
Choices B, C and D are incorrect because as the trees get darker, the camouflage of the peppered moth will be less effective, meaning it is more visible to predators and therefore more likely to be eaten.

Explanation:
Choice D is correct because transpiration is the loss of water from the stomata of a plant, it is not a stage of plant reproduction. Choices A, C and D are incorrect because pollination, fertilisation and seed dispersal are all stages of plant reproduction.

Explanation:
Choice D is correct because low blood glucose concentration is detected by the alpha cells in the pancreas and they respond by releasing glucagon. Choice A is incorrect because high blood concentration does not cause the secretion of glucagon and it is not secreted by beta cells. Choice B is incorrect because high blood concentration does not cause the secretion of glucagon, it causes the release of insulin. Choice C is incorrect because glucagon is not secreted by beta cells.

Explanation:
Facilitated diffusion and osmosis are both passive means of transport and therefore do not require energy.

Active transport (Choice A) requires energy expenditure. Facilitated diffusion is a passive form of transport but active transport requires energy (Choice B). Facilitated diffusion (Choice D) does not require energy expenditure but this answer choice does not include osmosis.

Explanation:
The four stages of mitosis are prophase, where chromosomes supercoil and become visible; Metaphase, where chromosomes line up at the equator of the cell; anaphase, where sister chromatids are pulled apart and telophase, where the nuclear envelope reforms and two new daughter nuclei are formed.

Statement I is incorrect as sister chromatids are not pulled apart during metaphase. They are pulled apart during anaphase.
Choice B is incorrect as both statements II and III are correct and should be included.

Explanation:
Choice A is correct because if the heart were placed in a hypotonic solution (as opposed to isotonic) water would diffuse into the cardiac muscles.

Choice B is incorrect because there would be no net movement into the tissues of the heart in an isotonic solution, not a hypotonic or hypertonic solution. Choice C is incorrect because even if it is placed in a solution other than an isotonic solution, it cannot dry out as it is still bathed in a watery solution. Choice D is incorrect as the tonicity of the solution the heart is stored in has no effect on whether the recipient’s immune system identifies the heart as foreign which would lead to rejection of the heart by the immune system.

Explanation:
A base substitution is when one nucleotide randomly replaces another in a sequence causing a single nucleotide polymorphism. This can result in a shorter polypeptide being translated (Statement I) due to the base change causing a stop codon to appear earlier in the DNA/mRNA sequence. It can also cause an altered polypeptide chain to be translated (Statement II) if the base substitution causes a different amino acid to be translated. It can also have no effect on the polypeptide that is translated (Statement III), as the genetic code is degenerate, meaning many codons code for the same amino acid. Choice D is therefore correct.

Choices A, B and C are incorrect, as they do not include all three statements.

Explanation:
Mitosis forms two genetically identical daughter cells with the same number of diploid chromosomes as the parent cell.

18 (Choice B) is incorrect as it is the haploid number of chromosomes. 72 (Choice C) is incorrect as it is twice the diploid number of chromosomes. 9 (Choice D) is incorrect as it is a quarter of the diploid number and an odd number.

Explanation:
The question states that heterozygous individuals have the banded pattern on their hairs, which means that the agouti trait is dominant. Two heterozygous parents will produce offspring with the dominant and recessive characteristics in the ratio of 3:1 (Choice B). The offspring of a heterozygous individual and a homozygous agouti individual will all receive at least one dominant allele, so they would all be agouti (Choice A). The offspring of at least one parent that is homozygous for agouti will all have the agouti characteristic (Choices C and D).

Explanation:
A greenhouse gas is a gas that contributes to the greenhouse effect. Greenhouse gases absorb the long wave infrared radiation (heat energy) emitted from Earth’s surface and can reradiate it back to Earth’s surface. So, one factor that determines whether a gas acts as a greenhouse gas is its ability to absorb long wave radiation: gases that are better able to absorb long wave radiation are more likely to act as greenhouse gases. A second factor that qualifies carbon dioxide as a greenhouse gas of concern is its relatively high concentration in the atmosphere: gases that are in higher concentration in the atmosphere have a larger effect on Earth’s temperature.

Explanation:
Statement III is not true, as homologous chromosomes often have different alleles (forms of genes), so are generally not identical to each other.

Statements I and II are true, as homologous chromosomes are pairs of chromosomes that have their centromeres and genes at the same positions. Therefore, Choice C is correct.

Explanation:
Choice C is correct because meiosis halves the number of chromosomes, mitosis maintains the diploid number and fertilisation restores the diploid number.

Choice A is incorrect because meiosis separates pairs of alleles and produces nuclei with one allele for each gene.

Choice B is incorrect because mitosis produces genetically identical cells that have two alleles for each gene.

Choice D is incorrect because, in fertilisation, two gametes fuse, and each gamete has one allele for each gene.

Explanation:
Choice A is correct because high blood glucose concentration is detected by the beta cells in the pancreas and they respond by releasing insulin. Choice B is incorrect because alpha cells produce glucagon and not insulin. Choice C is incorrect because the release of insulin is triggered by high blood glucose concentration and not low blood glucose concentration. Choice D is incorrect because low blood glucose concentration does not cause the release of insulin and insulin is not secreted by alpha cells.

Explanation:
The solution used to bathe organs to be used in a transplant should have an osmolarity equal to that of the organ to be transplanted and so the solution is isotonic compared to the organ’s tissues.

A solution with an osmolarity higher than that of the organ to be transplanted (Choice A) would cause tissue cells to shrivel, while a solution with an osmolarity lower than that of the organ to be transplanted (Choice B) would cause organ cells to burst. There are no described protocols that indicate that the solution should be mixed with cells from the organ to be transplanted (Choice D).

Explanation:
The graph shows an overall positive correlation, as maternal age increases, the incidence of non-disjunction increases (Choice A). Choice B is incorrect because there is a positive correlation not a negative correlation. Choice C is incorrect because there is a correlation. Choice D is incorrect because non-disjunction does occur below 35 years, but the incidence is lower when compared to above 35 years.

Explanation:
A mRNA strand contains four nitrogenous bases: adenine (A), cytosine (C), guanine (G) and uracil (U). It does not contain thymine (T) (Choice C and Choice D).

Most mRNA strands which code for polypeptides begin with the $\text{‘}$START$\text{’}$ codon AUG and end with a `STOP$\text{’}$ codon, UAG, UAA or UGA (Choice A). Choice B has a $\text{‘}$STOP$\text{’}$ codon at the beginning which would terminate translation before it begins.

Explanation:
The nuclear envelope is the membrane that separates the nucleus from the cytoplasm. For mitosis to proceed it must be broken down in the first stage of mitosis which is prophase so that the spindle fibres are able to attach to the centromeres. Choice A is correct.

Metaphase (Choice B), Anaphase (Choice C) and Telophase (Choice D) all follow Prophase (Choice A) in the sequence of mitosis and do not involve the breakdown of the nuclear envelope.

Explanation:
Choice B is correct because there are pairs of homologous chromosomes lined up on the equator, and each chromosome is attached to only one pole. Choice A is incorrect because in metaphase II, chromosomes are not in homologous pairs. Each chromosome, composed of sister chromatids, is attached to both poles. Choice C is incorrect because in anaphase I, homologous chromosomes are separated, and one chromosome from each pair is pulled to one pole. Choice D is incorrect because in telophase I, there are two sets of chromosomes that are already separated.

Explanation:
Sweat (Choice B) is a coolant and helps to cool the body.
Tears (Choice A), urine (Choice C) and saliva (Choice D) do not lower or raise the body temperature.

Explanation:
PCR is used to amplify samples of DNA so they can be used for analysis.

PCR replicates DNA but does not show that replication is semi-conservative (Choice A).

PCR does not determine the base sequence of DNA. It produces copies of short sections of DNA that can then be further analyzed (Choice B).

Taq polymerase is an enzyme used in PCR but no Taq DNA is incorporated. (Choice D).

Explanation:
Negative feedback is a regulatory mechanism in which the body responds to a change in order to return the homeostatic variable back to within its set points. For example, if blood pH increases above the set point, negative feedback mechanisms will occur to bring blood pH back down. Statement I is therefore true and Statement II is therefore false. Choices B and D are not correct.

While the nervous system plays a significant role in many feedback mechanisms, it is not the only system involved. The endocrine system, which releases hormones into the bloodstream also plays a crucial role in feedback control. Statement III is therefore false, meaning Choice B is incorrect, and Choice A is the correct response to the question.

Explanation:
Choice C is a correct definition of a gene. Chromosomes are made of DNA and protein (Choice A), while genes are only made of DNA. When DNA is at various levels of supercoiling, it is wrapped around histone proteins. However, the presence of histones is not part of the definition of a gene (Choice B). Genes control some characteristics, but some characteristics are also affected by the environment (Choice D).