Question

which statement about karyotype analysis is true?
it identifies epigenetic factors that cause certain phenotypes.
it can be used to determine how tall a baby will grow by adulthood.
it only detects issues with the sex chromosomes.
it can be used to detect trisomy 21 prenatally.

Explanation:

Karyotype analysis examines chromosome number and structure. Trisomy 21 (Down syndrome) involves an extra chromosome 21, which is visible in a karyotype. Prenatal karyotyping (e.g., from amniocentesis) can identify this. Epigenetic factors are not detected by karyotyping; height prediction is not its purpose; it detects issues with all chromosomes, not just sex chromosomes.

Answer:

It can be used to detect trisomy 21 prenatally.