Correct Answer: SKULL

Solution : Given – PALAEONTOLOGY : FOSSIL :: PHRENOLOGY : ?

The relationship between the word of the second pair and the given options should be the same as the first pair of words.

Option first: SKULL

The study of Skull is called Phrenology . Here, the relationship between the words is similar to the first pair.

Option second: THYROID

The study of Thyroid is called Endocrinology .

Option third: PANCREAS

The study of the Pancreas is called Pancreatology .

Option fourth: LUNGS

The study of Lungs is called Pulmonology .

Hence, first option is correct.