Answer:
Marine ecosystem have biotic organisms like phytoplankton and photosynthetic algae that do photosynthesis and converts the atmospheric carbon dioxide into organic matter most of the carbon dioxide is released when other organisms eat phytoplankton and release the carbon dioxide through respiration.
But some of the algae and phytoplanktons die naturally get down to the bottom of the ocean where they make carbon sink. Some organisms accumulate CO₂ in their exoskeleton that is made up of calcium carbonate.
Therefore this use of carbon by living organisms in oceans brings carbon dioxide from the atmosphere to oceans. This is why the ocean plays a critical role in the carbon cycle and called carbon sink.
Answer:
Fossils provide direct evidence of evolution. They show the changes of animals from ancient organisms to present form. Fossils are the preserved remains of earth layers. There are 4 types of fossils-
Original fossils that are not very old. e.g. teeth, skeleton, shells.
Frozen fossils
less permanent fossils
casts, molds, and prints - wings, skin, leaves, etc.
The fossils show the adaptive radiation in horses, humans. The transition fossils form the connecting link between different groups such as fish and amphibians, reptiles and birds, etc.
e.g. Archeopteryx is the connecting link between the reptiles and birds.
The modern horse Equus have several ancestor species, we came to know from the fossil records.
The fossil record shows the evolution of humans and their ancestors.
