Answer:
The second line of defence is nonspecific resistance, which kills intruders in a broad manner without focusing on specific individuals: phagocytic cells ingest and kill any germs that enter body tissues.
Explanation:
Answer:
The excretory system helps the respiratory system by removing carbon dioxide that is produced during respiration (third option).
Explanation:
The lungs are in charge of the breathing process, being the main organ of the respiratory system. Each lung is considered an excretory organ —belonging to the excretory system— since it is capable of eliminating the carbon dioxide (CO₂) produced by the metabolism during expiration.
As a result of the gaseous exchange, the oxygen entering the lungs through the inhaled air passes into the blood, while the CO₂ is removed from the blood. This CO₂ is removed during expiration, which makes the lungs part of the excretory system.
The other options are not correct because:
- <em>The excretory system does </em><u><em>not introduce more oxygen into the lungs</em></u><em>.
</em>
- <em>The </em><u><em>circulation of blood in and out of the lungs</em></u><em> is a function of the circulatory system.
</em>
- <u><em>Urine is not produced by breathing</em></u><em>.</em>
<h3><u>Answer and explanation;</u></h3>
- DNA is a double stranded molecule. Covalent and hydrogen bonds pray important roles in the functioning of DNA molecules.
- <em><u>Covalent bonds occur within each linear strand and strongly bond the nucleotide bases, sugars, and phosphate groups occurring both within each component and between components.</u></em>
- <em><u> Hydrogen bonds occur between the two strands and involve a base from one strand with a base from the second in complementary pairing.</u></em>
- Hydrogen bonds helps the complementary base pairs in DNA; guanine with cytosine and adenine with thymine to connect to one another. The hydrogen bonds between these complementary pairs helps keep the two strands of DNA helix together.
Bottleneck is the term used to define chance changes in the frequency of alleles which have a significant effect on small populations. The effect is that the population is greatly reduced because of the change in the allele frequency. A genetic drift will follow which will expedite evolution.
I think it is
C
Hope this help you?
