Consider statements about ribosomes: 1. They are non-membranous organelles. 2. Prokaryotic ribosomes are 80S. 3. They are the site of protein synthesis. Which are correct? MCQ with Answer and Explanation

Explanation:
Passive immunity is acquired by receiving pre-formed antibodies from another source, providing immediate but temporary protection. Examples: antivenom, immune globulin injections, and maternal antibodies. Active immunity is generated by the body's own immune system (infection or vaccination). Innate is non-specific, cell-mediated is T-cell based.

Explanation:
Implantation occurs about 6-7 days after fertilization, when the blastocyst embeds into the endometrium. Fertilization is sperm-egg fusion, ovulation egg release, menstruation shedding.

Explanation:
A point mutation is a genetic mutation where a single nucleotide base is changed, inserted, or deleted from a sequence of DNA or RNA. The classic example is sickle cell anemia, caused by a single point mutation in the beta-globin gene, where adenine is replaced by thymine, changing the amino acid from glutamic acid to valine.