Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow. 
Note : All plants belong to the same species. No pollen tube growth/inhibition of pollen germination on stigma. Pollen germination on stigma.
Student to attempt either option (A) or (B).
(A)
(i) Describe the process of megasporogenesis in an angiosperm.
(ii) Draw a diagram of a mature embryo sac of the angiosperm. Label its any four parts.
OR
(B) The reproductive cycle in the female primates is called menstrual cycle. The first menstruation begins at puberty.
Answer the following questions:
(i) Name the four phases of menstrual cycle in a proper sequence.
(ii) How long does the menstrual phase last in a menstrual cycle?
(iii) When and why hormones estrogen and progesterone reach their peak levels respectively, in the menstrual cycle?
(iv) Give the significance of LH surge.
Answer the following questions:
[(i)] Explain the structure of a mature embryo sac of a typical flowering plant.
[(ii)] How is triple fusion achieved in these plants?
OR
[(i)] Describe the changes in the ovary and the uterus as induced by the changes in the level of pituitary and ovarian hormones during menstrual cycle in a human female.
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is : 
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity 2K while that in the middle has thermal conductivity K. The left end of the combination is maintained at temperature 3T and the right end at T. The rods are thermally insulated from outside. In steady state, temperature at the left junction is \(T_1\) and that at the right junction is \(T_2\). The ratio \(T_1 / T_2\) is 
Sexual reproduction in flowering plants takes place or happens when the production of a new organism occurs from two parents by making use of their gametes or sex cells. Both sexual and asexual reproduction can be found in plants. Nearly all flowering plants reproduce sexually. Flowers play a captious role in the process as it carries both the male and female reproductive parts commonly known as androecium and gynoecium respectively.