Regarding assertion and reason, select the right option.
Assertion [A]: Mendel could not come up with physical proof for the existence of his factors, now known as genes or chromosomes.
Reason [R]: Chromosomes were discovered only after 1900 due to advancements in microscopy.
Both A and R are true and R explains A
It was only after 1900 that scientists were able to observe cell division which led to the discovery of structures in the nucleus that appeared to double and divide just before each cell division. They came to be known as chromosomes.