The air that we breathe is mostly made up of nitrogen (78%). 21% is oxygen which is needed for animals and humans in respiration and 0.03% is carbon dioxide which is needed for plants to make energy in a process called photosynthesis. The bit that is left is made up of rare gases like helium and argon and methane.
This is false
This selection and variation happens more gradually. It is hard to notice over a short period of time. The change is slow, constant and consistent. In punctuated equilibrium, the changes come in spurts. There are periods wherein a huge change occurs and there are also periods with very little change. The mutation is at random. Genetic drift is the change in the frequency of a gene variant due to a random sampling of organisms.
Answer:
a. the trp repressor dissociates from DNA.
Explanation:
trp operon is transcribed when:
Bonus: trip is present in low concentrations (not high concentration as option c suggest) inside the cell
Answer:
C. when a portion of the moon passes through the earth's umbral shadow.
Explanation:
A partial lunar eclipse occurs when the Earth passes between the sun and moon but the celestial bodies are not arranged in a straight line. When that occurs, a small part of the moon's surface is covered by the darkest, central part of the shadow of the Earth called the umbra. The rest is covered by the outer part of the shadow, termed penumbra.
Answer:
The classification system groups organisms in progressively more inclusive categories.
