Genes aren't the only factor. Because you inherit one APOE gene from your mother and another from your father, you have two copies of the APOE gene. Having at least one APOE e4 gene increases your risk of developing Alzheimer's disease. If you have two APOE e4 genes, your risk is even higher.
Simple Time Signatures. In simple time signatures, the beat falls on undotted notes such as quarter notes, half notes, eighth notes etc. Also, every beat is divisible by two. In 4/4 (also referred to as quadruple metre) the basic beat is a quarter note. This beat can be split into groups of two. By that I mean, a quarter note divides into eighth notes and eighth notes divide into sixteenth notes. Another example of a simple time signature is 3/4 also referred to as triple metre.
Basics of Meter. meter is a recurring pattern of stresses or accents that provide the pulse or beat of music. Meter is notated at the beginning of a composition with a time signature. Time signatures are always notated with two numbers, one on top of the other, much like a fraction in math. The top number denotes the number of beats in each measure. The bottom number denotes the note value that receives the beat.