Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Context: Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center. Energy levels are a little like the steps of a staircase. You can stand on one step or another but not in between the steps. The same goes for electrons. They can occupy one energy level or another but not the space between energy levels. The model in the Figure 1.1 shows the first four energy levels of an atom. Electrons in energy level I (also called energy level K) have the least amount of energy. As you go farther from the nucleus, electrons at higher levels have more energy, and their energy increases by a fixed, discrete amount. Electrons can jump from a lower to the next higher energy level if they absorb this amount of energy. Conversely, if electrons jump from a higher to a lower energy level, they give off energy, often in the form of light. This explains the fireworks pictured above. When the fireworks explode, electrons gain energy and jump to higher energy levels. When they jump back to their original energy levels, they release the energy as light. Different atoms have different arrangements of electrons, so they give off light of different colors. Q: In the atomic model Figure 1.1, where would you find electrons that have the most energy? A: Electrons with the most energy would be found in energy level IV. The smallest atoms are hydrogen atoms. They have just one electron orbiting the nucleus. That one electron is in the first energy level. Bigger atoms have more electrons. Electrons are always added to the lowest energy level first until it has the maximum number of electrons possible. Then electrons are added to the next higher energy level until that level is full, and so on. How many electrons can a given energy level hold? The maximum numbers of electrons possible for the first four energy levels are shown in the Figure 1.1. For example, energy level I can hold a maximum of two electrons, and energy level II can hold a maximum of eight electrons. The maximum number depends on the number of orbitals at a given energy level. An orbital is a volume of space within an atom where an electron is most likely to be found. As you can see by the images in the Figure 1.2, some orbitals are shaped like spheres (S orbitals) and some are shaped like dumbbells (P orbitals). There are other types of orbitals as well. Regardless of its shape, each orbital can hold a maximum of two electrons. Energy level I has just one orbital, so two electrons will fill this energy level. Energy level II has four orbitals, so it takes eight electrons to fill this energy level. Q: Energy level III can hold a maximum of 18 electrons. How many orbitals does this energy level have? A: At two electrons per orbital, this energy level must have nine orbitals. Electrons in the outermost energy level of an atom have a special significance. These electrons are called valence electrons, and they determine many of the properties of an atom. An atom is most stable if its outermost energy level contains as many electrons as it can hold. For example, helium has two electrons, both in the first energy level. This energy level can hold only two electrons, so heliums only energy level is full. This makes helium a very stable element. In other words, its atoms are unlikely to react with other atoms. Consider the elements fluorine and lithium, modeled in the Figure 1.3. Fluorine has seven of eight possible electrons in its outermost energy level, which is energy level II. It would be more stable if it had one more electron because this would fill its outermost energy level. Lithium, on the other hand, has just one of eight possible electrons in its outermost energy level (also energy level II). It would be more stable if it had one less electron because it would have a full outer energy level (now energy level I). Both fluorine and lithium are 
 Question: any atom is most stable when its outermost energy level contains
as many electrons as it can hold.

Context: Christianson syndrome (CS) is an X-linked neurodevelopmental and neurological disorder characterized in males by core symptoms that include non-verbal status, intellectual disability, epilepsy, truncal ataxia, postnatal microcephaly and hyperkinesis. CS is caused by mutations in the SLC9A6 gene, which encodes a multipass transmembrane sodium (potassium)-hydrogen exchanger 6 (NHE6) protein, functional in early recycling endosomes. The extent and variability of the CS phenotype in female heterozygotes, who presumably express the wild-type and mutant SLC9A6 alleles mosaically as a result of X-chromosome inactivation (XCI), have not yet been systematically characterized. Slc9a6 knockout mice (Slc9a6 KO) were generated by insertion of the bacterial lacZ/-galactosidase (-Gal) reporter into exon 6 of the X-linked gene. Mutant Slc9a6 KO male mice have been shown to develop late endosomal/lysosomal dysfunction associated with glycolipid accumulation in selected neuronal populations and patterned degeneration of Purkinje cells (PCs). In heterozygous female Slc9a6 KO mice, -Gal serves as a transcriptional/XCI reporter and thus facilitates testing of effects of mosaic expression of the mutant allele on penetrance of the abnormal phenotype. Using -Gal, we demonstrated mosaic expression of the mutant Slc9a6 allele and mosaically distributed lysosomal glycolipid accumulation and PC pathology in the brains of heterozygous Slc9a6 KO female mice. At the behavioral level, we showed that heterozygous female mice suffer from visuospatial memory and motor coordination deficits similar to but less severe than those observed in X-chromosome hemizygous mutant males. Our studies in heterozygous Slc9a6 KO female mice provide important clues for understanding the likely phenotypic range of Christianson syndrome among females heterozygous for SLC9A6 mutations and might improve diagnostic practice and genetic counseling by helping to characterize this presumably underappreciated patient/carrier group. 
 Question: Mutation of which gene is implicated in the Christianson syndrome?
slc9a6

Context: Tobacco companies are fighting efforts in the United States and Australia to make their products less appealing. In Washington, a federal judge last week blocked the Food and Drug Administration from requiring new warning labels on cigarette packs. Judge Richard Leon ruled in a case brought by five tobacco companies. The judge temporarily stopped a new federal rule which requires large new warnings starting next September. These include color1 images such as a dead body or diseased lungs. And simple text warnings now appear. Congress called for color1 images showing the dangers of smoking, similar to what Canada does. But the tobacco companies say the new requirements approved in June violate their free speech rights guaranteed by the Constitution. Judge Leon said the FDA could not require the new labels before a lawsuit against the government is decided. Some experts say the process could take years. The judge said he believed the cigarette makers were highly likely to win their case. He said the images should be designed to appeal to emotions, rejecting government arguments that they should be purely factual. He accused the government of trying to use the labels to promote an "obvious anti-smoking agenda?" The head of an anti-smoking group, the Campaign for Tobacco-Free Kids, called the decision "wrong on the science and wrong on the law". About one-fifth of American adults smoke. The World Health Organization says tobacco kills nearly six mil-lion people worldwide each year. More than six hundred thousand of them are non-smokers who breathe other people's tobacco smoke. In Australia, tobacco companies want to stop what would be the world's most restrictive laws on cigarette advertising. Cigarettes could be sold only in plain olive-green packages. Only the brand name and health warnings could appear. The Senate passed the bill last week and sent it back to the Lower House to approve minor amendments . The law is to go into effect in December of next year. Tobacco companies Say the legislation violates the Australian constitution. They say it would unjustly reduce the value of their brand names and trademarks. Health Minister Nicola Roxon says the government is ready for a legal fight. 
 Question: Which country has adopted color1 images showing the dangers of smoking as warning labels?

canada.