Match the metals of Column - I with the biological origin of Column - II :
`{:((A),"Chromium",(p),"Chloroplast"),((B),"Iron",(q),"Haemoglobin"),((C),"Zinc",(r),"Eyes of cats and cows"),((D),"Calcium",(s),"Prown"),(,,(t),"Bones"):}`

Answer

To match the metals from Column - I with their biological origins in Column - II, we need to analyze the properties and roles of each metal listed in Column - I.

### Step-by-Step Solution:

1. **Identify the Metals and Their Biological Roles**:
- **Chromium (A)**: Chromium is known to play a role in glucose metabolism and is often associated with insulin. However, it is not directly linked to chloroplasts.
- **Iron (B)**: Iron is a critical component of hemoglobin, which is responsible for transporting oxygen in the blood.
- **Zinc (C)**: Zinc is essential for various biological functions, including vision. It is known to be present in the eyes of cats and cows.
- **Calcium (D)**: Calcium is vital for bone structure and health. It is also found in shells and is important for various biological processes.

2. **Match Each Metal with Its Biological Origin**:
- **Chromium (A)**: Does not match with any of the options directly, but it is not linked to chloroplasts.
- **Iron (B)**: Matches with (q) "Haemoglobin".
- **Zinc (C)**: Matches with (r) "Eyes of cats and cows".
- **Calcium (D)**: Matches with (t) "Bones".

3. **Final Matching**:
- (A) Chromium - (p) Chloroplast (not a direct match)
- (B) Iron - (q) Haemoglobin
- (C) Zinc - (r) Eyes of cats and cows
- (D) Calcium - (t) Bones

### Summary of Matches:
- A - p (not a direct match)
- B - q
- C - r
- D - t