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

Introduction / Context:
Sexual reproduction in flowering plants involves the transfer of pollen grains from the male structures to the female structures of the flower. The female reproductive organ is called the carpel or pistil and is divided into distinct parts, each with a specific function. Knowing which part receives pollen is key to understanding pollination, fertilization, and seed formation in botany. This question asks you to name the terminal, often sticky part of the carpel that captures pollen grains.

Given Data / Assumptions:
• The question focuses on the carpel, the female part of a flower. • Important parts are stigma, style, and ovary. • Anther, a male structure, is also listed as a distractor option.

Concept / Approach:
A typical carpel consists of three main parts. The stigma is the uppermost terminal part, often sticky or feathery, which receives pollen grains. The style is the slender stalk that connects the stigma to the ovary. The ovary is the swollen basal part that contains ovules, which develop into seeds after fertilization. The anther, in contrast, is part of the stamen, the male organ, and produces pollen. Therefore, the correct answer must be stigma, the sticky terminal portion of the carpel that functions as the pollen receiving surface.

Step-by-Step Solution:
Step 1: Recall the structure of the carpel: stigma at the top, style in the middle, and ovary at the base. Step 2: Remember that the stigma has a sticky or feathery surface to efficiently catch and hold pollen grains during pollination. Step 3: Understand that the style serves mainly as a passage through which pollen tubes grow downwards toward the ovary. Step 4: Note that the ovary contains ovules but does not directly receive pollen on its surface in typical descriptions. Step 5: Exclude the anther because it is part of the male organ (stamen) and is the source of pollen rather than the receiver.

Verification / Alternative check:
Standard diagrams of a flower show pollen grains landing on the stigma. From the stigma, pollen tubes germinate and grow through the style to reach the ovary, where fertilization occurs. The functional sequence in plant reproduction always begins with pollen adherence to the stigma, confirming that the stigma is the pollen receiving structure. This makes stigma the only accurate answer.

Why Other Options Are Wrong:
Option A (Ovary) is incorrect because it is the basal part that contains ovules and later develops into fruit. Option B (Style) is incorrect because it mainly supports the stigma and provides a path for pollen tubes, but does not primarily function as the pollen receiving surface. Option D (Anther) is incorrect because anther is the pollen producing part of the stamen, the male reproductive structure, not part of the carpel.

Common Pitfalls:
Learners sometimes confuse male and female structures and may select anther simply because they associate it strongly with pollen. Others may think that since seeds form in the ovary, pollen must land there directly. Remember that pollen first lands on the stigma, then pollen tubes grow down the style, and only then does fertilization occur in the ovary. This sequence clarifies why stigma is the pollen receiving part of the carpel.

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