Answer: Hydrogen bonds are created between the base pairs in DNA. Adenine pairs with thymine and cytosine pairs with guanine. Adenine and thymine create 2 hydrogen bonds while cytosine and guanine create 3. These bonds are fairly weak so that they can be broken when DNA is replicated (by an enzyme called helicase which unwinds DNA). However despite them being weak they do stabilize DNA's double helix structure as well.
Answer:
C. Exocytosis uses transport vesicles to export materials from the cell
Explanation:
Exocytosis is the reverse process of endocytosis including the expulsion of the material that is membrane -encapsulated (material is packaged in the vesicles ) inside the cell out of the cell. It has following steps :
1) The cell forms a vesicle around a material which is to be expelled.
2) The vesicle is transported to the cell membrane.
3) The vesicle membrane fuses with the cell membrane and releases the contents from the cell.
Hence option C. Exocytosis uses transport vesicles to export materials from the cell IS THE RIGHT OPTION.
When liquid water is exposed to 32 Fahrenheit, it get freeze. It is because it is freezing point of water
Answer: The tracheids have important functions in the plant.
Explanation: The mechanical support is provided by the lignified walls of tracheid cell. the helps in other functions of the plant such as transporting water and getting the solute from the root to the stem and eventually the leaf of the plant.
The tracheids are most useful in the gymnosperms where elements need to be transported.
Identifying a tracheid in a cross section is quire easy as the tracheid cells fit into each other neatly and piled up similarly and have identical shapes as well which makes them obvious from other cells.
The two examples of tracheid plans could be
The most common thing that could be found in traceid plant is that this cells are mainly present for transporting either water other solutes in the plant body.
