The fossil record shows that some animals, such as the horseshoe crab, have existed unchanged for millions of years. other organisms, such as pigs, have undergone a well-documented sequences of changes. which type of organism would be most useful as an index fossil? explain your answer.

Answer;

Pigs would be more useful as an index fossil.

Explanation; An index fossil is an animal or plant that is preserved in rock record of the earth and has a characteristic of a certain period of geologic time or environment. A useful index fossil must be abundant, easily recognizable, and have a geographic distribution.Pigs would be a useful index fossil because the well-documented changes that occurred in the fossil record would help geologists determine the ages of rocks much more than the unchanging horseshoe crabs.

Hunting in the darksome fish rely on senses beyond sight. in the darkness of the marianas trench, a fish called the rattail has an extremely sensitive sense of smell. the fish uses scent, rather than sight, to steer toward food. once it's near food, the rattail uses a special organ on the bottom of its chin to guide itself by feel.marine snowone staple of the deep sea diet is "marine snow," flakes of organic, edible substances that sink down from the upper ocean. animals at the ocean's bottom find sustenance in everything from the bodies of dead creatures to fecal matter. marine snow is diverse enough to support numerous species. for instance, several species of snails and worms feed exclusively on deceased whales.microorganismsthe deep sea is an intricate ecosystem, and even the ocean floor itself plays a part. hydrothermal vents are cracks in the sea floor where erupting magma mixes with ocean water to produce plumes of hot, sulfur-rich chemicals. some microbes can use these chemicals for energy, sustaining their existence and that of the animals who depend on their roles in the deep sea food chain.

3. is true i think i should be right