Which digestive enzyme breaks down lactose into glucose and galactose? MCQ with Answer and Explanation

Explanation:
Bacteria exhibit diverse nutritional modes; some are autotrophic (photosynthetic like cyanobacteria or chemosynthetic), while others are heterotrophic (saprophytic or parasitic). Fungi are eukaryotic organisms, characterized by having a true nucleus and membrane-bound organelles, and are heterotrophic. Viruses are considered non-living outside a host cell because they lack metabolic machinery and cannot replicate independently; they only exhibit living characteristics inside a host. Thus, statements 1 and 3 are correct.

Explanation:
Meiosis is reductional division occurring in germ cells to produce haploid gametes (n) from a diploid cell (2n). It involves two successive divisions (Meiosis I and II) and introduces genetic variation through crossing over and independent assortment. Mitosis maintains chromosome number, amitosis is direct division, and fission is asexual reproduction in prokaryotes.

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.