Answer:
1. Bacteria where grow in a medium composed of heavy nitrogen. After several generations the bacteria DNA was composed of heavy nitrogen (heavy nitrogen is an isotope of nitrogen).
2. After several generations had passed, the bacteria were transferred to a nitrogen light medium.
3. As soon as the bacteria were transferred the bacteria DNA was isolated after the first and second generation through centrifugation.
4. Results: after 2 generations half of the DNA was intermediate and half was light; there was not heavy-only DNA. The conclusion was that the new DNA is formed by an "old" strand and a "new" strand producing an intermediate weight.
A - The alveoli have a membrane that is only one cell thick to allow for a short diffusion time to capillaries.
Answer:
Based on the relative volumes of the gases in Earth’s atmosphere, nitrogen is actually more than 3 times more than oxygen. Because the troposphere is the lowest atmosphere layer, it contains 75 percent of the atmosphere’s mass.. From largest to smallest, Earth’s atmosphere composition contains nitrogen, oxygen, argon, CO 2 and trace gases.
Explanation:
Pollution and digging oil wells. Pollution contaminates the Earth and digging oil wells can cause earthquakes.
Answer:
A zygote can end up with one fewer chromosome than normal because one of the fertilizing gametes was missing a chromosome. This deletion, called nondisjunction, happened while the gamete was forming.
Explanation:
