I believe that the chemical buffers provide the shortest term mechanisms for preventing acid-base imbalances in the body. Chemical buffers normally act within a fraction of a second to resist a pH change. On the other hand the longest mechanism is the kidney system which ordinarily requires from several hours to a day or more to affect changes in blood pH.
Answer:
The presence of pillow lavas in the oldest preserved volcanic sequences on the planet, the Isua and Barberton greenstone belts, confirms the presence of large bodies of water on the Earth's surface early in the Archean Eon. Pillow lavas are used generally to confirm subaqueous volcanism in metamorphic belts.
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Answer A:
1. Spiral chloroplast:
This organelle help in photosynthesis, because it contain green pigment called chlorophyll in which water and carbon dioxide combine in the presences of sun light to prepare glucose.
2. Cell wall:
It is chemically composed of<span> an outer layer of pectin and an inner layer of cellulose. It provide rigidity and shape to spirogyra cell.</span>
Answer B:
The other parts which are not labelled include mucilage, cytoplasm, pyrenoids, cytoplasmic strand.
Answer C:
Function of pyrenoid:
<span>Each chloroplast strand has several round bodies called 'pyrenoids', which are responsible for starch production.
</span>Function of mucilage:
Mucilage help in retaining water in cell.
Answer: D. a fertilized egg cell
Totipotent stem cells are cells which are formed when a sperm fertilizes a egg resulting in a zygote. A zygote being a totipotent stem cell divides many times to develop specialized cells in a new human being. Therefore, a fertilized egg cell has greatest number of totipotent stem cells.
