The ……..(i) …... very in colour from olive green to various shades of brown depending upon the amount …....(ii)……..

Options

A. (i) red algae (ii) phycobilins
B. (i) green algae (ii) chlorophyll
C. (i) brown algae (ii) chlorophyll
D. (i) brown algae (ii) carotenoids

Answer

To solve the question, we need to fill in the blanks with the correct terms related to algae and their pigmentation.

### Step-by-Step Solution:

1. **Identify the type of algae**:
The question mentions that the algae vary in color from olive green to various shades of brown. This description fits **brown algae** (Phaeophyceae), which are known for their varying shades due to their pigments.

**Hint**: Consider the types of algae and their color characteristics.

2. **Determine the pigment responsible for the color variation**:
The color variation in brown algae is primarily due to the presence of different pigments. While chlorophyll is present, the key pigments that contribute to the brown coloration are **carotenoids** (specifically, xanthophylls). The amount of these pigments can cause the algae to appear in different shades.

**Hint**: Think about the pigments found in brown algae and how they contribute to color.

3. **Fill in the blanks**:
Based on the analysis:
- For the first blank (i), the answer is **brown algae**.
- For the second blank (ii), the answer is **carotenoid**.

Therefore, the complete sentence reads: "The **brown algae** vary in color from olive green to various shades of brown depending upon the amount **of carotenoid**."

### Final Answer:
The brown algae vary in color from olive green to various shades of brown depending upon the amount of carotenoid.