Consider the following statements about the human nervous system: 1. The sympathetic nervous system prepares the body for fight-or-flight. 2. The parasympathetic nervous system has a calming effect. 3. Both are part of the somatic nervous system. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
Most bacteria possess a single circular double-stranded DNA molecule located in the nucleoid region. Some bacteria may also have linear chromosomes or multiple chromosomes, but the typical prokaryotic chromosome is circular. Eukaryotes have linear chromosomes. Plasmids are small, circular extra-chromosomal DNA in bacteria.

Explanation:
Meiosis I is the reductional division where homologous chromosomes separate, reducing the chromosome number from diploid (2n) to haploid (n). Meiosis II is equational division, similar to mitosis, separating sister chromatids. Thus, reduction occurs in anaphase I. DNA replication occurs in S phase before meiosis I. Gametes are haploid. Errors in reduction can lead to aneuploidy.

Explanation:
Reverse transcriptase is an enzyme unique to retroviruses that transcribes single-stranded RNA into double-stranded DNA (cDNA). This DNA integrates into the host genome. DNA polymerase synthesizes DNA from DNA, RNA polymerase from DNA. Reverse transcriptase is used in RT-PCR and cDNA synthesis.