Certain marine brown and red algae produce large amounts of hydrocolloids eg. (A)____ and (B)____, respectively which are used commerically.

Answer

To solve the question regarding the hydrocolloids produced by marine brown and red algae, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Hydrocolloids**:
- Hydrocolloids are substances that can hold water, which makes them useful in various commercial applications.

2. **Identify the Types of Algae**:
- The question specifies two types of marine algae: brown algae and red algae.

3. **Research Hydrocolloids from Brown Algae**:
- Brown algae are known to produce a hydrocolloid called **algin**. Algin is widely used in the food industry as a thickening agent and stabilizer.

4. **Research Hydrocolloids from Red Algae**:
- Red algae produce a hydrocolloid known as **carrageenan**. Carrageenan is also used in the food industry, particularly in dairy products and as a thickening agent.

5. **Fill in the Blanks**:
- Based on the information gathered:
- (A) = algin (from brown algae)
- (B) = carrageenan (from red algae)

### Final Answer:
- (A) algin
- (B) carrageenan