Final answer:
The assertion that the law of independent assortment can be studied through dihybrid crosses is true. The reason provided, pertaining to only linked genes showing independent assortment, is false; unlinked genes show independent assortment.
Step-by-step explanation:
The law of independent assortment states that the alleles for different genes usually segregate independently of each other. This can be observed in a dihybrid cross, which involves two genes on different chromosomes, for instance, seed color and seed texture in pea plants. The assertion that the law of independent assortment can be studied through dihybrid crosses is true because it allows us to observe how different traits are passed on from the parents to the offspring independently. However, the reason presented is false. Independent assortment occurs for genes that are not physically linked on the same chromosome; genes that are physically linked, or gene linkage, do not assort independently unless crossing over separates them. Therefore, the correct answer is:
- c. Assertion is true, but the reason is false.