I am not totally sure but I think it’s B
Answer:
Indirect contact transmission occurs when there is no direct human-to-human contact.
Explanation:
There are two types of contact transmission: direct and indirect. Direct contact transmission occurs when there is physical contact between an infected person and a susceptible person. Indirect contact transmission occurs when there is no direct human-to-human contact.
Carbon dioxide concentrations in soil are higher than in the atmosphere because of respiration of the plants, their roots. Also, CO2 is inhigherr concentration because of the decomposition of organic matter. Decomposition of organic matter produce more CO2 because of increased microbial activity. CO2 concentrations can change as a result of temperature change or different soil structure. Composition of air in soil and atmosphere of CO2 is
<span>Soil Air: 0.25% Atmosphere: 0.04%.</span>
Nucleotide bases are added to DNA strands in a 5' to 3' direction.
What is DNA replication?
When a cell divides, DNA copies itself through a process called replication.
- Generally speaking, DNA replication involves uncoiling the helix, strand separation by rupturing the hydrogen bonds between the complementary strands, and synthesis of two new strands through complimentary base pairing.
- The origin of replication, which is a precise location in the DNA, is where replication starts.
- From the point of origin, DNA replication is bidirectional.
- The two parent DNA strands unwind and split apart at the origin of replication to generate two "Y-shaped" replication forks in order to start DNA replication.
- These unwinding enzymes are known as DNA helicases.
- The real location of DNA copying is at these replication forks.
- Proteins that destabilize helices bind to the single-stranded areas to prevent the two strands from rejoining.
- To reduce stress on the helical molecule during replication, enzymes known as topoisomerases cause breaks in the DNA and then reunite them.
- The hydrogen bonding of free DNA nucleotides with those on each parent strand results in the formation of new complementary strands as the strands continue to unwind and split in both directions around the entire DNA molecule.
- The new nucleotides are joined by DNA polymerases using phosphodiester bonds as they align themselves opposite each parent strand using hydrogen bonds.
- Deoxynucleotide triphosphates, which are made up of a nitrogenous base called deoxyribose and three phosphates, are the actual nucleotides that are aligning through complementary base pairing.
- Two of the phosphates are withdrawn to provide energy for bonding as the phosphodiester bond forms between the 3' OH of the previous nucleotide in the DNA strand and the 5' phosphate group of the next nucleotide.
- In the end, two identical DNA molecules are created when each parent strand acts as a template for the synthesis of a complementary copy of itself.
Hence, nucleotide bases are added to DNA strands in a 5' to 3' direction.
To learn more about DNA replication click on the link
brainly.com/question/21265857
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