The disease caused by the bacterium Bordetella pertussis is: MCQ with Answer and Explanation

Explanation:
Telomerase is a ribonucleoprotein enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (telomeres), preventing them from shortening during DNA replication. It is highly active in germ cells, stem cells, and most cancer cells, granting them replicative immortality. In most normal somatic cells, telomerase is inactive, leading to gradual telomere shortening and cellular aging.

Explanation:
Synapsis (pairing of homologous chromosomes) and crossing over (exchange of genetic material) occur during prophase I of meiosis, not in mitosis. Mitosis involves one division producing two genetically identical diploid daughter cells. Meiosis involves two divisions producing four haploid gametes with genetic variation. Chromosome duplication and sister chromatid separation occur in both. Spindle fibres form in both divisions. Thus, synapsis and crossing over are unique to meiosis.

Explanation:
Bacterial infections (like tuberculosis, pneumonia) are effectively treated with antibiotics, which target specific bacterial structures or metabolic pathways. Many viral diseases (like polio, measles, influenza) can be prevented through vaccination, which stimulates the immune system to develop memory against the virus. Fungal diseases (like ringworm, candidiasis) are caused by fungi, not protozoa; protozoa cause diseases like malaria and amoebiasis. Thus, statements 1 and 2 are correct.