Consider statements about biotechnology: 1. Restriction enzymes cut DNA at specific sequences. 2. DNA ligase joins DNA fragments together. 3. PCR is used to sequence DNA. Which are correct? MCQ with Answer and Explanation

Explanation:
In primary succession on a bare, lifeless rock (xerosere), the pioneer species are usually lichens (a symbiotic association of fungi and algae or cyanobacteria). Lichens can survive in harsh, dry conditions and secrete acids that slowly weather the rock, contributing to soil formation. Once a thin layer of soil is formed, mosses can colonize, followed by herbs, grasses, shrubs, and eventually a climax forest community.

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:
Erythropoietin (EPO), produced mainly by the kidneys in response to low oxygen levels, stimulates the bone marrow to produce red blood cells. Insulin regulates glucose, thrombopoietin stimulates platelet production, aldosterone regulates sodium and potassium balance.