Double fertilization is a characteristic feature of: MCQ with Answer and Explanation

Explanation:
Helicase unwinds the DNA helix at the replication fork by breaking hydrogen bonds between base pairs. DNA polymerase adds nucleotides, ligase seals Okazaki fragments, primase synthesizes RNA primer. This coordinated action ensures accurate semi-conservative replication. Without helicase, the strands would not separate. Energy for unwinding comes from ATP hydrolysis.

Explanation:
Histology is the microscopic study of tissues—groups of cells with similar structure and function. Cytology deals with cells, anatomy with gross body structures, morphology with form and external features. Histological techniques involve staining and microscopy to examine tissue architecture in health and disease.

Explanation:
Ethylene is a gaseous plant hormone that promotes fruit ripening (climacteric fruits like banana, apple), leaf abscission, and senescence. Auxin, gibberellin, and cytokinin primarily promote growth. Ethylene is used commercially to ripen fruits uniformly. It also stimulates the formation of abscission layers and inhibits stem elongation.