During swallowing, the air passageway of the phaynx is covered by the epiglottis
Hydrogen bonds.
The question asks for bonds BETWEEN molecules NOT WITHIN molecules. A covalent bond occurs WITHIN water molecules between hydrogen and oxygen.
Hydrogen bonds occur BETWEEN water molecules; HYDROGENS of water molecules form a hydrogen bond (a type of intermolecular force) with electronegative OXYGEN atoms of other water molecules.
Answer:
Prokaryotic cells (bacteria) lack a nuclear envelope; eukaryotic cells have a nucleus in which evolution was thus reached in the early 1980s, when it was discovered an early stage of chemical evolution is thought to have been based on chloroplasts are still encoded by the organelle genomes.
Explanation:
Answer:
Upwelling
Explanation:
Upwelling is the process through which cold water gets to ascends from the bottom, providing nutrients to the superficial stratum.
Upwelling is an ascending displacement of marine currents. The phenomenon<em> can also occur in lakes or freshwater dams</em>.
Wind blowing over the coast can cause surface water to move out to sea. This motion is complemented by a slow ascension of cold water coming from the bottom forward to the coast. This currents movement is known as upwelling.
Upwelling water is extremely cold and rich in nutrients, which result from remineralization, by bacterial action, of organic matter that accumulates in the deepest stratum of the water body.
The contact of minerals with photosynthesizing organisms in superficial layers produces a significantly high primary productivity.