In this question, we are given a list of geological time scales (List-I) and a list of corresponding life forms (List-II). We are asked to match the items from List-I with the correct items from List-II.

In the given answer choice 1, the matches are as follows:

A. Pleistocene - 2. Mammals

B. Paleocene - 1. Human genus

C. Permian - 4. Frogs

D. Cambrian - 3. Invertebrates

This means that during the Pleistocene era, mammals existed. In the Paleocene era, the human genus existed. During the Permian era, frogs existed. And during the Cambrian era, invertebrates existed.

All the matches in option 1 are correct. Therefore, the correct answer is option 1.

No alert is necessary as the given answer is correct.