Step 1: Understanding the iodoform test.
The iodoform test is used to detect compounds that contain a methyl group directly attached to a carbonyl group, such as ketones or alcohols with the structure \( \text{R-COCH}_3 \). The presence of a yellow precipitate of iodoform (\( CHI_3 \)) indicates a positive result.
Step 2: Analyzing the options.
(A) CH\(_3\)COCH\(_3\) and C\(_2\)H\(_5\)OH: Correct — Acetone (CH\(_3\)COCH\(_3\)) will give a positive iodoform test, but ethanol (C\(_2\)H\(_5\)OH) will not.
(B) C\(_2\)H\(_5\)OH and CH\(_3\)OH: Incorrect — Neither ethanol nor methanol will give a positive iodoform test.
(C) CH\(_3\)COCH\(_3\) and C\(_6\)H\(_5\)COCH\(_3\): Incorrect — Both acetone and acetophenone will give a positive iodoform test.
(D) C\(_6\)H\(_5\)COCH\(_3\) and C\(_2\)H\(_5\)OH: Correct— Only acetophenone will give a positive iodoform test.
Step 3: Conclusion.
The correct answer is:
(A) CH\(_3\)COCH\(_3\) and C\(_2\)H\(_5\)OH
(D) C\(_6\)H\(_5\)COCH\(_3\) and C\(_2\)H\(_5\)OH
Arrange the following set of carbocations in order of decreasing stability.

Choose the correct answer from the options given below:
Identify the taxa that constitute a paraphyletic group in the given phylogenetic tree.
The vector, shown in the figure, has promoter and RBS sequences in the 300 bp region between the restriction sites for enzymes X and Y. There are no other sites for X and Y in the vector. The promoter is directed towards the Y site. The insert containing only an ORF provides 3 fragments after digestion with both enzymes X and Y. The ORF is cloned in the correct orientation in the vector using the single restriction enzyme Y. The size of the largest fragment of the recombinant plasmid expressing the ORF upon digestion with enzyme X is ........... bp. (answer in integer) 