Which of the following is $NOT$ a vestigial organ in humans?

Fossil $X$ is older than fossil $Y$ if

The banding pattern of modern humans and chimpanzees is nearly identical. This indicates that both have:

Choose the correct statements with reference to organic evolution.
$I.$ Flippers of whale and wings of bat exhibit analogy.
$II.$ Wings of butterfly and wings of bird exhibit homology.
$III.$ Organs with dissimilar structure are called analogous organs.
$IV.$ Organs with similar structure and origin are called homologous organs.

In evolution,studies can be conducted at the molecular level. For example,proteins found in the blood of humans and apes are similar. The base sequences in nucleic acids and amino acid sequences in proteins are similar in related organisms. What do all these examples specifically refer to?

Fossil $X$ is older than fossil $Y$. The most evident answer is: