A mutation that involves the change of a single nucleotide base in the DNA sequence is called a: MCQ with Answer and Explanation

Explanation:
Robert Hooke, in his 1665 book 'Micrographia', described observing dead cork tissue under a microscope and coined the term 'cell' for the small, box-like compartments he saw. Antonie van Leeuwenhoek, using his superior handcrafted single-lens microscopes in the 1670s, was the first person to observe and describe living, single-celled microorganisms, which he called 'animalcules'. Charles Darwin proposed the theory of evolution by natural selection; the cell theory was proposed by Schleiden and Schwann. Thus, statements 1 and 2 are correct.

Explanation:
Lenticels are small, raised pores in the bark (periderm) of woody stems and roots that permit gas exchange between internal tissues and the atmosphere. Stomata are on leaves, hydathodes are for guttation, sclereids are sclerenchyma cells. Lenticels are filled with loosely arranged complementary cells and are visible as small dots on the surface of bark.

Explanation:
Helicobacter pylori is a spiral-shaped bacterium that colonizes the stomach lining, disrupting the mucous layer and causing inflammation, leading to gastric and duodenal ulcers. It was discovered by Barry Marshall and Robin Warren (Nobel 2005). S. pneumoniae causes pneumonia, E. coli is gut microbiota but some strains cause diarrhea, B. subtilis is a harmless soil bacterium.