Since males have only x-chromosome they are more likely to express x-linked (by far the most common type of sex - linked disorders ) recessive traits. females can also not express any y-linked traits. females have a backup copy of the genes on their other x-chromosome, similar to autosomal chromosomes.
If this is a true/false question, the answer is true. oxygen and co2 exchange happens at the capillaries.
The scientific theory contains many steps. It could also be known as a hypothesis. Hope this is helpful
If those are the optional answers, it's most likely sodium.