Answer:
Troposphere.
Explanation:
Humans live most of their lives in the troposphere atmosphere.
Prophase of mitosis do the chromosomes become distinctly visible in the microscope.
During metaphase, the nucleus dissolves and the cell's chromosomes condense and move together, aligning in the center of the dividing cell. At this stage, the chromosomes are distinguishable when viewed through a microscope. The first stage of mitosis and of meiosis I and II.
During prophase the chromosomes become visible as distinct structures, the nuclear envelope breaks down, and a spindle forms (Meiotic prophase I is more complex, and includes synapsis of homologous chromosomes and crossing over). During Prophase chromosomes become Clearly visible, nuclear envelope disappears, kinetochores and spindle fibers form.
To learn more about prophase , here
brainly.com/question/13883655
#SPJ4
Random changes in allele frequency in a population are usually called genetic drift. The reason why this is the answer is because it is a very specific word which is used to describe exactly that - random changes in allele frequency.
All the other cases; answers, here aren't correct and don't apply.
Don't trust me on this one, but i'll say d.
Answer: A.) The nitrogen cycle recycles nitrogen through an ecosystem, making it available to all organisms.
Explanation: Nitrogen is an essential nutrient for plants and a significant component of proteins, which all animals need to grow, reproduce and survive. The nitrogen cycle converts nitrogen into compounds that plants and animals can use.