(a) Study the diagram (Diagram 1.1) given below showing the modes of pollination. Answer the questions that follow.

i) The given diagram shows three methods of pollen transfer in plants. What are the technical terms used for pollen transfer methods '1', '2' and '3' ?

ii) How do the following plants achieve pollination successfully ?

1. Water lily

2.Vallisneria

iii) Flowering plants have developed many devices to avoid inbreeding depression. Explain one hereditary and one physiological device which helps plants to achieve this target.

or

(b) Observe the diagram (Diagram 1.2) given below showing the menstrual cycle of a normal human female and answer the questions that follow :

i) What are the suitable technical terms used for the following ? 1. Days 1-7 2. Days 8-12 3. Days 16-28 4. Days 13-15

ii) Explain the role of ovarian and pituitary hormones during the following time periods :

1. Days 8-12

2. Days 13-15

3. Days 16-28

Correct Answer/Option:
(a)
i)
1. Autogamy
2. Geitonogamy
3. Xenogamy
ii)
1. Water lily: pollinated by insects/wind.
2. Vallisneria: Female flowers on long stalks reach the water surface; male flowers or pollen are released on the water surface and carried by water currents to the female flowers to achieve pollination.
iii)
Genetic (Hereditary): Self-incompatibility, which prevents self-pollen (from the same flower or other flowers of the same plant) from fertilizing the ovules by inhibiting pollen germination or pollen tube growth in the pistil.
Physiological: Pollen release and stigma receptivity are not synchronized; either the pollen matures earlier and the stigma matures later, or vice versa.
or
(b)
i)
1. Days 1-7: Menstrual period
2. Days 8-12: Follicular phase / proliferative phase
3. Days 16-28: Luteal phase / secretory phase
4. Days 13-15: Ovulatory phase
ii) The role of ovarian and pituitary hormones as shown in the provided chart:
- Days 8-12: Ovarian hormones lead to follicular growth and proliferation of endometrial cells. Pituitary hormones stimulate follicular development and the secretion of estrogen by the growing follicles.
- Days 13-15: Ovarian hormones facilitate the maturation of ovarian follicles, formation of Graafian follicles, and thickening of the endometrium. Pituitary hormones trigger the rupture of the Graafian follicle to release the ovum (LH surge).
- Days 16-28 (represented as Days 16-18 in the image table): Ovarian hormones maintain the endometrium, while pituitary hormones/ovarian luteal activity lead to the secretion of progesterone from the corpus luteum.

### Detailed Step-by-Step Explanation

Part (a) Analysis:
i) Technical Terms for Pollen Transfer (Diagram 1.1):
By analyzing Diagram 1.1, we observe three distinct pathways of pollen transfer indicated by the numbers 1, 2, and 3:
1. Autogamy (Method 1): The arrow shows pollen transfer from the anther to the stigma of the same flower. This is a type of self-pollination.
2. Geitonogamy (Method 2): The arrow indicates pollen transfer from the anther of one flower to the stigma of another flower on the same plant. Functionally, this is cross-pollination involving a pollinating agent, but genetically it is similar to autogamy since the pollen grains come from the same plant.
3. Xenogamy (Method 3): The arrow displays pollen transfer from the anther of a flower on one plant to the stigma of a flower on a different plant of the same species. This introduces genetic variation.

ii) Pollination in Aquatic Plants:
1. Water Lily: Although it is an aquatic plant, its flowers emerge above the level of water and are pollinated by insects or wind, similar to land plants.
2. Vallisneria: This plant exhibits hydrophily. The female flower reaches the water surface by a long, coiled stalk. The male flowers or pollen grains are released onto the surface of the water and are passively carried by water currents until they make contact with the female flowers.

iii) Outbreeding Devices to Avoid Inbreeding Depression:
- Genetic/Hereditary Device (Self-incompatibility): This is a genetic mechanism that prevents self-pollen from fertilizing the ovules of the same flower or other flowers of the same plant by inhibiting pollen germination or pollen tube growth in the pistil.
- Physiological Device (Dichogamy): This involves non-synchronized pollen release and stigma receptivity. Self-pollination is prevented because either the pollen is released before the stigma becomes receptive (protandry) or the stigma becomes receptive before the release of pollen (protogyny).

Part (b) Analysis:
i) Menstrual Cycle Phases (Diagram 1.2):
Based on the circular calendar in Diagram 1.2 showing the days of the menstrual cycle:
1. Days 1-7: The breakdown of the endometrial lining occurs, which is the Menstrual period.
2. Days 8-12: The primary follicles grow to become fully mature Graafian follicles, and the endometrium regenerates through proliferation; this is the Follicular phase / proliferative phase.
3. Days 13-15: The mid-cycle phase where ovulation occurs is the Ovulatory phase.
4. Days 16-28: The ruptured Graafian follicle transforms into the corpus luteum, secreting progesterone; this is the Luteal phase / secretory phase.

ii) Hormonal Control (Image Table):
Looking at the second image table, we map the activities of ovarian and pituitary hormones:
1. Days 8-12: Gonadotropins (LH and FSH) from the pituitary stimulate follicular development and secretion of estrogens by the growing follicles. Estrogen, an ovarian hormone, stimulates the proliferation of the endometrium.
2. Days 13-15: Both LH and FSH attain a peak level in the middle of the cycle. The rapid secretion of LH (LH surge) induces the rupture of the Graafian follicle and thereby the release of the ovum (ovulation). Estrogen levels remain high to mature the follicles.
3. Days 16-28: The corpus luteum secretes large amounts of progesterone, which is essential for the maintenance of the endometrium, preparing it for possible implantation.