Pollen grain _________has prominent apertures called ___________where sporopollenin is __

Options

A. intine, germpore, absent
B. exine, germpore, absent
C. exine, germpore, presetn
D. exine, foramen ovale, absent

Answer

To fill in the blanks in the question "Pollen grain _________ has prominent apertures called __________ where sporopollenin is __," we can follow these steps:

1. **Identify the Structure of Pollen Grain**:
- Pollen grains are the male gametophytes in flowering plants. They consist of two layers: the outer layer called the exine and the inner layer called the intine.

2. **Understand the Composition of Pollen Grain**:
- The outer layer (exine) is made of a tough substance called sporopollenin, which is known for its resistance to degradation. The inner layer (intine) is made up of cellulose and pectin.

3. **Recognize the Apertures in Pollen Grains**:
- Pollen grains have specific openings called apertures. These are areas where the exine is thinner and allows for the formation of the pollen tube during fertilization.

4. **Fill in the Blanks**:
- The first blank refers to the pollen grain's structure, which is "exine".
- The second blank refers to the specific type of apertures, which are called "germ pores".
- The third blank indicates where sporopollenin is not present, which is "absent" in the germ pores.

Thus, the completed sentence is: "Pollen grain **exine** has prominent apertures called **germ pores** where sporopollenin is **absent**."