Preserved remains of organisms are called:

Correct option is A

The correct answer is (a) Fossil

Explanation:
• Fossils are the preserved remains or traces of organisms that lived in the past.
• Fossils can include bones, shells, footprints, and even imprints of plants and animals that have been preserved in rock over millions of years.
• The process of fossilization typically occurs when the remains of organisms are buried by sediment, and over time, minerals in the sediment replace the original organic material, preserving it in the rock.
• Fossils provide valuable information about the history of life on Earth, allowing scientists to study past ecosystems, climates, and evolutionary processes.

Information Booster:
• Fossils are found in sedimentary rocks, which form from layers of sediment that accumulate over time.
• Fossilization is a rare process, as conditions must be just right for an organism's remains to be preserved.

Additional Knowledge:
(b) Rock:
• While fossils are often found in rocks, particularly sedimentary rocks, rocks themselves are not preserved remains of organisms.
• Rocks are naturally occurring solid aggregates of minerals and do not contain biological material unless they contain fossils.

(c) Depression:
• A depression in geological terms refers to a low area or basin in the Earth's surface, not the preserved remains of organisms.
• It may be a site where fossils could be found, but a depression itself is not a type of preserved organism.

(d) All of these:
• This option is incorrect because while fossils are the preserved remains of organisms, rocks and depressions are not. Only fossils qualify as preserved remains.