A person has a sex-linked inheritable disease. Which statement is true about the set of chromosomes which are likely to carry the genes for this disease? 1-The gene is present on a single pair of chromosomes.
2-The gene is present multiple pairs of chromosomes.
3-The gene is always present on an X chromosome.
4-The gene is always present on a Y chromosome.

Answer Choice:  3.) The gene is always present on an X chromosome

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

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