The answer is: It is an explanation for an observation.
Explanation:
A hypothesis is a suggested explanation that is both testable and falsifiable. You must be able to test your hypothesis, and it must be possible to prove your hypothesis true or false.
1. Interphase is an important and the longest phase of the cell cycle during which the cell prepares for division by coping its DNA. It is metabolic phase of the cell, in which the cell grows, obtains nutrients and metabolizes them. There are three stages of interphase: G1 (the cell growth), S (replication of DNA, chromosomes are copied) and G2 (preparation for division). Without this phase, genetic material wouldn’t be ready for the process of meiosis and haploid gametes couldn’t be created.
2. Homologous chromosomes are the similar but not totally identical chromosome pairs that an organism receives from its two parents. During the prophase I of meiosis they pair up: each chromosome aligns with its homologue partner via link-chiasmata ( the two match up at corresponding positions). Those homologue pairs separate during a first stage of cell division (meiosis I-reduction of chromosomes number, from diploid to haploid), while sister chromatids separate during a second stage (meiosis II).
3. Crossing over is a process in which homologous chromosomes trade their parts. Crossing over is process of genetic recombination where DNA is cut and then repaired. Cut and repair of homologous chromosomes allow them to exchange some of their genetic information. As a consequence of crossing over, new arrangement of maternal and paternal alleles on the same chromosome is achieved. It is the way to create varations.
4. During the metaphase I, homologue pairs are lined up comparing to metaphase II where individual chromosomes are lined up. It is because during the meiosis I homologue pairs separate and chromosome number reduce from diploid to haploid. On the other hand, during the meiosis II, sister chromatids separate.
5. Nondisjunction is the consequence of cell division, where there is no properly separation. There are different forms of nondisjunction:
• failure of a pair of homologous chromosomes to separate in meiosis I,
• failure of sister chromatids to separate during meiosis II.
After nondisjunction, resulting daughter cells are with abnormal chromosome numbers -aneuploidy.
Answer:
Prophase; when the nuclear envelope breaks down,
prometaphase; the physical barrier that encloses the nucleus, called the nuclear envelope, breaks down
metaphase; The chromosomes line up across the center of the cell
anaphase; The centromeres split
telophase; The chromosomes begin to stretch out and lose their rod-like appearance
Ans.
Nitrogen fertilizers are commonly used by farmers to increase crop production. Ammonium is the main component of nitrogen fertilizer, as it is easily assimilated by plants and provides nitrogen to them, while nitrate gets easily lost from the soil. During nitrogen cycle, ammonium is converted into nitrate by nitrification. So, nitrification inhibitors are used with to slow down the conversion of ammonium to nitrate to provide nitrogen for longer time.
Thus, 'to increase crop production, nitrification step of nitrogen cycle is preferred by farmers to block, or slow down.'
