In grasses, certain (A)___ epidermal cells along the veins modify themselves into large, empty, colourless cells. These cells are called (B)_____ cells.

Answer

To solve the question, we need to identify the two blanks (A) and (B) based on the information provided in the transcript.

1. **Understanding the context**: The question refers to specific epidermal cells in grasses that modify into large, empty, colorless cells. We need to identify what type of epidermal cells these are (A) and what the large, empty cells are called (B).

2. **Identifying A**: The transcript mentions that the epidermal cells that modify are located along the veins and are part of the upper epidermis. The upper epidermis is also referred to as the adaxial surface. Therefore, we can conclude that (A) refers to "adaxial".

3. **Identifying B**: The transcript states that the modified cells are large, colorless, and help in storing water. These cells are specifically called "bulliform cells" or "motor cells". Thus, (B) refers to "bulliform cells".

Putting it all together, we can fill in the blanks:

- (A) = adaxial
- (B) = bulliform cells

**Final Answer**: In grasses, certain (A) **adaxial** epidermal cells along the veins modify themselves into large, empty, colorless cells. These cells are called (B) **bulliform cells**.