The precancerous lesion associated with tobacco use that looks like a thickened, flat white patch on the mucous membrane of the mouth is

Ans. 'Leukoplakia.'

Leukoplakia is characterized by development of flat, thickened, white patches, on the lining of mucous membrane of mouth and tongue. The most common cause of leukoplakia is smoking due to chronic irritation of cells from tobacco.

These patches are also known as precancerous lesions as more serious cases can lead to development of oral cancer.

Thus, the correct word to be filled in the blank is 'leukoplakia.'

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above

the answer is :