What is meant by "gaps" within living things or fossils? 1. missing links
2. a distinct and obvious lack of transition between all higher levels of taxa
3. specimens representing evidence for evolutionary transitions

Option (1)

Explanation:

The missing link refers to those fossils that are believed to be connecting two separate groups of organisms in their stages of evolution. They had the characteristics of both the group of organisms. These are the extinct species, and only the traces of it are found to be embedded in some rocks. So there is no proper evidence that supports their existence in the past.

They are considered to be hypothetical, diminished organisms that occur during the evolutionary stages of a group of organism. They are also known as the 'gaps' within living things or fossils.

Thus, the correct answer is option (1).