The the time period during which a species lived and the the distribution of its fossils, the better an index fossil the species is. shorter; narrower shorter; wider longer; narrower longer; wider

Option (2)

Explanation:

Index fossils are defined as those fossils that had a wide geographical distribution and they were present for a comparatively shorter period of time. They had great significance in the field of paleontology. It helped in the construction of geological periods that are commonly used today. It basically helped in forming the geological time scale. The age of the rocks in which these fossils were embedded is easily determined by using radioactive dating techniques.

Thus, the index fossils have a shorter time period and wider geographical distribution of fossils.

Hence, the correct answer is option (2).

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

answer: c.

explanation: