Answer:
In the 1960s, scientists found evidence that new material is indeed erupting along mid-ocean ridges. The scientists dived to the ocean floor in Alvin, a small submarine built to withstand the crushing pressures four kilometers down in the ocean. In a ridge’s central valley, Alvin’s crew found strange rocks shaped like pillows or like toothpaste squeezed from a tube. Such rocks form only when molten material hardens quickly after erupting under water. These rocks showed that molten material has erupted again and again along the mid-ocean ridge.
When scientists studied patterns in the rocks of the ocean floor, they found more support for sea-floor spreading. You read earlier that Earth behaves like a giant magnet, with a north pole and a south pole. Surprisingly, Earth’s magnetic poles have reversed themselves many times during Earth’s history. The last reversal happened 780,000 years ago. If the magnetic poles suddenly reversed themselves today, you would find that your compass needle points south.
Explanation:
I found this somewhere.
Answer:
Less than the effect of each drug added together.
Explanation:
Because it could harm wildlife.
Answer:
a. preventing the cross-linkage of NAM subunits
Explanation:
The bacterial cell wall is made of peptidoglycan which is a polymer of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues. The NAM residues are crosslinked to impart additional strength to the cell wall.
Most of the antibiotics that target the cell wall synthesis in bacteria inhibit the enzyme of transpeptidation which in turn cross-links the NAM residues of the polysaccharide chains of the bacterial cell wall. Examples of these antibiotics include penicillins and cephalosporins.
Answer:
Limiting variables include a low supply of food and lack of room. Limiting variables may reduce birth rates, increase death rates, or contribute to emigration. Limiting factors determine a population's carrying capacity. Recall that the population grows exponentially when there are no limiting factors.
Explanation:
Hope this helps you!
