There are 5 levels of cell organization recognized by biologists.
Answer:
<u>Cilia</u>
Explanation:
Cilia and flagellum are made up of microtubules.
Cytoskeletal filaments are structures which allow movement. In cilia and flagella, the cytoskeletal filaments are present in the form of microtubules and the primary work of these structures is to facilitate in movement.
Cilia is also present in mammals to facilitate the movement of fluids in cells.
Structurally, there is no difference between cilia and flagella. The only difference between cilia and flagella is in their lengths.
Answer:
It is pertinent to understand what hypertonic, hypotonic, and isotonic solution means before setting out to explain how a cell reaches equilibrium in each type of solution.
A hypertonic solution is one whose solute concentration is higher than that of the sap of a cell that is immersed in it.
A hypotonic solution is one with the same solute concentration as that of the sap of the cell immersed in it.
An isotonic solution has a lower solute concentration than that of the sap of the cell immersed in it.
In biological systems, water molecules move by osmosis from the region of higher water potential or lower concentration of solutes to the region of lower water potential or higher concentration of solute. An equilibrium is reached when there is no net movement of water between two sides. Hence;
A cell placed in a hypertonic solution will lose water to the surrounding solution until an equilibrium is reached. This means that such a cell will end up shrinking (wilting) or even dying due to loss of water from the cell sap.
A cell placed in a hypotonic solution will gain water from the surrounding solution until there is no net movement of water anymore. Such a cell might become turgid or even burst out its cell content.
A cell placed in an isotonic solution will neither gain nor lose water because the cell sap and the surrounding solution have equal solute concentrations.
Explanation:
Answer:
The fish did not yet exist when the old layers of rocks were deposited. In fact, animals with hard parts did not evolve until about 600 million years ago, which is only about 13% of the 4.5 billion year age of the Earth. Multicellular animals without hard parts left tracks in older sediments, but had no fossilize-able body parts.
Explanation:
