The Mass Number of an Atom Is Equal to the Number

question 37

Multiple Choice

The mass number of an atom is equal to the number of

• A)electrons.
• B)neutrons.
• C)protons.
• D)protons plus neutrons.

---

Definitions:

Huntington Disease

A hereditary disorder caused by a genetic mutation, leading to the progressive degeneration of nerve cells in the brain.

Recessive Gene

A genetic trait that is expressed in an organism's phenotype only if two copies of the gene are present, but is masked if a dominant gene is present.

Dominant Gene

A gene that expresses its phenotypic trait even when only one copy is present in the genotype.

Recessive

A genetic term describing an allele that produces its characteristic phenotype only when its paired allele is identical.