The human respiratory system is basically the circulation of the body. the lungs which produces air/oxygen that cycles around the body which produces oxygen.
Carbon makes four electrons available to form covalent chemical bonds, allowing carbon atoms to form multiple stable bonds with other small atoms, including hydrogen, oxygen, and nitrogen. This allows carbon atoms to form a tremendous variety of very large and complex molecules.
Answer:
Examples of abiotic factors are water, air, soil, sunlight, and minerals. Biotic factors are living or once-living organisms in the ecosystem. These are obtained from the biosphere and are capable of reproduction. Examples of biotic factors are animals, birds, plants, fungi, and other similar organisms.
When the temperature reaches 0˚C (32˚F), the top layer of the lake freezes and turns into ice. In solid form, water molecules are less dense and thus ice floats on the top of the lake.
This solid barrier prevents any wind-induced mixing as well as protects the relatively warm water underneath. Furthermore, light is also blocked so that photosynthesis is inhibited during this period. As the lake water is separated from the atmosphere, no direct oxygen diffusion occurs.
All these factors together causes a more even distribution of nutrients and gases in a lake in winter.
