The enzyme used to join DNA fragments in genetic engineering is: MCQ with Answer and Explanation

Explanation:
Ciliated pseudostratified columnar epithelium (with goblet cells) lines the trachea and bronchi; the cilia beat in coordinated waves to move mucus and trapped particles out of the airways. Squamous epithelium is flat (alveoli), cuboidal in kidney tubules, transitional in urinary bladder.

Explanation:
Bacterial infections (like tuberculosis, pneumonia) are effectively treated with antibiotics, which target specific bacterial structures or metabolic pathways. Many viral diseases (like polio, measles, influenza) can be prevented through vaccination, which stimulates the immune system to develop memory against the virus. Fungal diseases (like ringworm, candidiasis) are caused by fungi, not protozoa; protozoa cause diseases like malaria and amoebiasis. Thus, statements 1 and 2 are correct.

Explanation:
Penicillin targets the transpeptidase enzyme, blocking peptidoglycan cross-linking, leading to cell lysis. This is the mechanism, so R correctly explains A.