Pinna is absent in

Options

A. Whale
B. Platypus
C. Seal
D. All of these

Answer

To solve the question "Pinna is absent in", we can follow these steps:

### Step 1: Understand what Pinna is
- Pinna refers to the visible part of the outer ear. It is made up of cartilage and serves the function of channeling sound waves into the external auditory canal.

### Step 2: Identify the presence of Pinna in different organisms
- Pinna is typically present in most mammals. However, there are exceptions where certain mammals do not have a well-defined pinna.

### Step 3: Analyze the options provided
- The question likely provides multiple options, including various mammals. We need to identify which of these options represent mammals that lack a pinna.

### Step 4: Recognize the mammals without Pinna
- Some mammals, such as certain species of whales and seals, have either a very reduced pinna or lack it entirely. This adaptation is due to their aquatic lifestyle.

### Step 5: Conclude the answer
- If the options include animals like whales, seals, or other similar aquatic mammals, we can conclude that the pinna is absent in these organisms. Therefore, if the options provided are all aquatic mammals, the correct answer would be "all of these".

### Final Answer
- The correct answer is option 4: "All of these", as pinna is absent in the mentioned aquatic mammals.

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