Which techniques are commonly used for studying individual chromosomes?

The correct answer is based on the techniques that specifically allow for the visualization and analysis of individual chromosomes. Karyotyping and banding techniques are traditional methods used in genetics to obtain a display of an individual's chromosomes, which can be categorized by size, shape, and number.

Karyotyping involves staining the chromosomes and arranging them in pairs to assess chromosomal abnormalities, such as aneuploidies or structural rearrangements. Banding techniques, such as G-banding, stain the chromosomes to produce a distinctive banding pattern that helps identify each chromosome and diagnose genetic disorders.

While other techniques like electrophoresis, PCR, and sequencing have their applications, they are typically used for analyzing DNA or RNA rather than directly studying whole chromosomes in terms of structure or number. Fluorescence and microscopy are useful but are generally employed in conjunction with karyotyping or banding techniques rather than as standalone methods specifically for studying individual chromosomes.