(i) Smallest animal virus
(ii) Largest animal virus
(iii) Smallest plant virus
(iv) Largest plant virus.

Explanation

To answer the question regarding the smallest and largest animal and plant viruses, we can break it down step by step:

### Step 1: Identify the Smallest Animal Virus
- The smallest animal virus is the **Foot and Mouth Virus**.
- Its size ranges from **0.008 to 0.012 microns**.

### Step 2: Identify the Largest Animal Virus
- The largest animal virus is the **Pox Virus**.
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