In the structure of a flower, what is the name of the terminal part of the carpel that is often sticky and receives pollen grains?

Introduction / Context:
This botany question focuses on the parts of the female reproductive structure of a flower, known as the carpel or pistil. Identifying the stigma, style, and ovary is fundamental in plant morphology and reproduction. The question specifically asks about the terminal part that may be sticky and is responsible for receiving pollen grains during pollination.

Given Data / Assumptions:
- The options list ovary, style, stigma, and anther. - The question refers to the terminal part of the carpel that may be sticky. - Basic knowledge of floral structure is assumed from school level botany.

Concept / Approach:
A typical carpel consists of three main parts. The ovary is the basal enlarged portion containing ovules. The style is a slender stalk that connects the ovary to the top. The stigma is the terminal part at the top of the style. The stigma is usually sticky or feathery to efficiently capture and hold pollen grains during pollination. The anther, on the other hand, is part of the stamen, the male reproductive organ, not the carpel. Therefore, the correct answer must be stigma.

Step-by-Step Solution:
Step 1: Recall that the carpel or pistil is the female reproductive part and includes stigma, style, and ovary. Step 2: Remember that the ovary is the lower part that encloses the ovules. Step 3: Note that the style is a slender elongated structure that supports the stigma and connects it to the ovary. Step 4: Identify that the stigma is the uppermost, frequently sticky region where pollen grains land and germinate. Step 5: Recognise that the anther belongs to the stamen and produces pollen but is not part of the carpel. Step 6: Conclude that the terminal sticky part of the carpel is the stigma.

Verification / Alternative check:
Textbook diagrams of typical flowers clearly label the stigma at the top of the pistil, often shown as a slightly enlarged, sometimes lobed or feathery surface. Descriptions emphasise that it is sticky or moist to capture pollen and allow pollen tube germination. No such description applies to the ovary or style. The anther is always shown attached to a filament as part of the stamen, not at the tip of the carpel. This visual confirmation strongly supports stigma as the correct answer.

Why Other Options Are Wrong:
Ovary: This is the basal part of the carpel that encloses ovules and later develops into fruit, not the terminal sticky region. Style: This is the stalk like portion connecting stigma and ovary and does not normally serve as the pollen receiving surface. Anther: This structure belongs to the male part, the stamen, and produces pollen rather than receiving it.

Common Pitfalls:
A common error is to confuse stigma and style because both are parts of the same structure and appear close together in diagrams. Another pitfall is to mistake the anther as part of the female organ since it is also associated with pollen. Careful reading that the question refers to the carpel and to the part that receives pollen should guide you to stigma. Memorising the sequence stigma, style, ovary from top to bottom can help avoid such confusion.

Final Answer:
The terminal sticky part of the carpel that receives pollen grains is the Stigma.