One fourth means (one half) of (one half) .
So the 18 months must be two half-lifes.
The half-life of this particular isotope is 9 months.
I believe the answer should be solar
Answer:
Coal and oil (if there are two answers)
Answer:
c) Habitat isolation
Explanation:
Habitat isolation is a mechanism that prevents species from mating even if they don't have reproductive barriers. The differences in the habitat types may thus be sufficient to develop reproductive isolation between two (or more) populations
Answer:
The correct answer is - biological hierarchy.
Explanation:
Biological hierarchy can be understand as the comprehension of the simplest form of the life to the most broadest and complex form of the life. It includes from the atoms which is a smallest structure and cells to the interactions of in between non living things and living things.
The broadest or highest level of the organization is biosphere in biological hierarchy in includes all other living organisms with non living things present in it. atoms to cell, tissue, organ, organ system to organism. these organisms shows interaction with each other and called populations that form communities, to ecosystem and finally biosphere.
Thus, the correct answer is - biological hierarchy.