Pure water is very close to a pH of 7. The Great Salt Lake (from what I've read about) can range from 8.2 to 7.7 in different areas. Saliva is between 6.5 and 7.5. And ammonia has a pH of 11.
So the items that have a pH between 5 and 8 are pure water, saliva, and possibly the Great Salt Lake.
The reason why nost scientists thought that the first true cells formed on Earth were anaerobic is being shown in the second option :B. because there was no oxygen on early Earth. Paying attention to this fact scientists discovered that first cells were prokaryotes and greatest part of them created oxygen as a toxic by-product of their own metabolism which make them understand how the planet was provided with oxygen and made a conclusion that first cells were anaerobic.
Answer:
The second statement is correct: "The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach."
Explanation:
The virus attaching itself to the host cell is the first step for it to successfully infect the host. Viruses are smaller in size than bacteria, so the first statement is incorrect. The third statement is incorrect because viruses do not have the necessary machinery to carry out protein synthesis or to generate ATP, this precisely why they seek out a host to begin with. The fourth statement is false because the virus will either have DNA or RNA, but both at the same time.
Hope that answers the question, have a great day!
Answer:
water molecules undergo the 'tug of war' via the cohesion-adhesion theory
Explanation:
In plants specifically, a transpiration stream is formed via osmosis from roots into xylem and travels by the apoplast pathway to the leaves, where the water then evaporates from stomata into the surrounding air along the diffusion gradient. the water loss from the mesophyll cells lowers their water potential therefore water moves in via osmosis by both apoplast and symplast pathway from adjacent cells. water bonded to water= cohesion, water bonded to carbohydrates of xylem walls= adhesion. water is drawn up in tug of war-esc fashion against gravity to replace water evaporated, resulting in cohesion-adhesion theory.
<h2>Answer:</h2>
Bacteria provide genetic engineers with <u>_vector_ </u>and <u>_host_.</u>
<h3>Explanation:</h3>
Vector are vehicles or carriers which are used to carry the gene of interest. They are usually plasmids which are bacterial circular genome which can replicate independently.
Hence bacterial plasmids are used for the insertion of gene of interest and its transfer to the host cell.
As plasmids is taken from the bacteria, so mostly bacteria is used as the host for the gene of interest.
