One type of muscular dystrophy, Duchenne muscular dystrophy, is is an inherited condition that usually only affects boys. Muscle weakness is noticed as children begin to walk or run. Characteristic signs include walking on tiptoe and large calves. The disease occurs in one out of every 3000 newborn male children. Why is this disease limited to mostly boys?

Explanation:

Duchenne muscular dystrophy acts as a X-linked recessive disease. Which means the gene sits on the X chromosome, and you need two bad copies to show disease (for females) and one bad copy (to show in males).

Now from our knowledge, we know males are XY and females are XX. Males have only one copy of the X chromosome from their mother and one copy of the Y chromosome from their father, thus if they get the mutated version of the gene that causes this disease, they will get the disease. However, if a female has a mutated version of gene on one of the X chromosome, the other X chromosome could have a normal gene and that normal gene would take over and produce a normal phenotype/function.

Since, boys only have one X chromosome, if they get the mutated gene they will get the disease, whereas females have two X chromosome (so even if one copy is bad and the other is good, the good version can take over, however boys don't have this) thus mostly male children are affected by this.

the function of the protein macromolecule is to move things in and out of the cell and transport other molecules in the body. there are many functions of proteins. they are the basic building blocks of living things and are responsible for the growth and repair of body cells and tissues.

explanation:

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.