Answer: False
Explanation:
Protozoans are not the organism that fix nitrogen for the plants. The organism that fix nitrogen to convert it into a form which can be used by plants are known as diazotrophs.
These are bacteria and archae that fix nitrogen gas found in the atmosphere into more usable form such as ammonia.
These organism can grow without any external source of fixed nitrogen. Example: Rhizobia and azospirillium.
Answer:
C. Molecules such as cyclins are in high concentration in the cytoplasm of a dividing cell and will signal the fused cells nucleus to undergo mitosis
Explanation:
Various stages of the cell cycle are under tight regulation. Specific proteins such as cyclins and cyclin-dependent protein kinases determine if the cell would progress from one stage of the cell cycle to the next. When a cell is in the metaphase, the cyclins specific for mitosis are present in a higher amount in the cell. These cyclins bind to the specific CDKs and activate them.
The activated CDKs then phosphorylate proteins that make the cell to move through various stages of mitosis. Therefore, fusing a G1 cell with a cell in metaphase of mitosis would trigger mitosis in the G1 cell due to the presence of mitosis specific cyclins in the second cell.
Hydrogen bonds allow for cohesion and adhesion. Think water properties
Answer:
The correct model is D.
Note: The first attachment below shows the different models. The second attachment shows the correct structural model of the water molecule.
Explanation:
A water molecule is composed of one atom of oxygen and two atoms of hydrogen.
A water molecule is polar, i.e. it contains positively and negatively opposite ends. The polar nature of the water molecule is due to strong electronegativity of oxygen which results in an uneven sharing of the bonding electrons between oxygen and hydrogen. The oxygen atom attracts the shared electrons more to itself, thereby, it acquires a partial negative charge, while the hydrogen atoms acquire a partial positive charge.
The bond angle between the oxygen and hydrogen atoms is approximately 105°. Therefore, from the first attachment below, the correct model for the water molecule is D.
Answer:
Obviously, such rocks transmit only small quantities of water and are poor aquifers. By comparison, rocks such as fractured sandstones and cavernous limestone have large connected openings that permit water to move more freely; such rocks transmit larger quantities of water and are good aquifers.
Explanation:
