Answer:
C. could not provide a mechanism for moving continents
Explanation:
Without the discovery of magnetic reversals recorded on the ocean floor, scientists could not provide a mechanism for moving continents.
Magnetic reversals are responsible for geological shifts and depend on the distribution of tectonic plates that causes movements of continents.
Asymmetric movement of tectonic plates leads to movement of continents and the degree of asymmetry varies with the same rythm of the magnetic reversal rate.
Hence, discovery of magnetic reversals are important to identify the mechanism for moving continents.
D. cellular respiration and photosynthesis
<span>A scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules.
A scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell. The movement of macromolecules of polysaccharides or proteins out of or into the cell is known as Bulk transport.
Bulk transport is of two types which include endocytosis and exocytosis whereby both require an expenditure of energy. Exocytosis materials are being exported out of the cell via secretory vesicles.
Golgi complex they do package macromolecules into transport vesicles which travel to and spill its content out of cells. Exocytosis is very much important in the expulsion of waste materials out of the cell and also in products secretion. Endocytosis is the process where materials move into the cell.
Endocytosis is divided into the three types which include pinocytosis, phagocytosis, and receptor-mediated endocytosis.</span>
The correct answer is: b. It is free to bind to another promoter and begin transcription
Transcription is the first step of gene expression in which DNA molecule is copied (transcribed) into RNA (mRNA) by RNA polymerase. The process of transcription is divided into three phases:
1. Initiation
• RNA polymerase with transcriptional factors bind to gene promoter
• RNA polymerase unwinds DNA double helix (transcription bubble is formed)
2. Elongation
• RNA polymerases adds nucleotides complementary to DNA
3. Termination
• RNA polymerase gets to stop codon (transcribes a sequence of DNA known as a terminator)
• Formed complementary RNA strand is released from DNA-RNA complex.
RNA polymerase is also released and can transcribe some other gene by binding to its promotor. RNA polymerase will transcribe just the genes whose products are needed at a particular moment.
