The sequence of event for the evolution of the atmosphere: 1. meteorite bombardment 2. Volcanic Outgassing 3. Oceans Form 4. Banded Iron Formations Created 5. cyanobacteria evolve 6. Oxygen increases in atmosphere 7. Eukaryotes evolve
The border between the
transparent edge of the cornea and the white of the fibrous sclera is the limbus.
The limbus contains clusters of limbal stem cells that help to maintain the corneal
epithelium and to regulate corneal transparency and vision throughout life. The
limbus also acts as a boundary that protects the conjunctiva and its blood
vessels.
Answer:
Although more offsprings are produced by the process of external fertilization but the process of internal fertilization is more efficient as compared to external fertilization. This is because, in external fertilization, it is more difficult for the sperm to find the egg and fertilize it. Even after fertilization, it might be that the zygote gets eaten up by a predator. There are none such risks in internal fertilization. The zygote is protected during the internal fertilization which makes this process more efficient.
Cellular respiration and photosynthesis are important parts of the carbon cycle. The carbon cycle is the pathways through which carbon is recycled in the biosphere. While cellular respiration releases carbon dioxide into the environment, photosynthesis pulls carbon dioxide out of the atmosphere. The exchange of carbon dioxide and oxygen during photosynthesis (Figure below) and cellular respiration worldwide helps to keep atmospheric oxygen and carbon dioxide at stable levels.
