A medical researcher has isolated a chemical from cigarette smoke. When the scientist mixes a small amount of the substance with living human cells, the chemical damages unsaturated fatty acids in the cells' plasma membranes. He is able to prevent this damage by adding vitamin E to the mixture of the chemical and cells. Based on this information, the scientist has . determined that the chemical in cigarette smoke is an oxidizing agent discovered a vitamin-based cure for lung cancer conducted an in vitro experiment under poorly controlled conditions identified vitamin E as a prooxidant

Option A, determined that the chemical in cigarette smoke is an oxidizing agent

Explanation:

Unsaturated fatty acids in the cells' plasma membranes such as phospholipids, cholesterol, and proteins contain double bonds between its constituting elements. An oxidizing agent breaks down this double bonds and starts destructing the essential macro molecules. Addition of vitamin E prevents lipid peroxidation chain reactions as it disrupts the propagation of lipid radicals. Therefore, when vitamin E is added, the damage of macromolecule reduces and hence stops.  

Hence, option A is correct

tissue

explanation:

it is actually formed by geoup of cells which is tissue

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.