With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte

From the statements given below choose the option that are true for a typical female gametophyte of (i) It is 8-nucleate and 7-celled at maturity (ii) It is free-nuclear during the development. (iii) It is situated inside the integument but outside the nucellus. (iv) It has an egg apparatus situated at the chalazal end (A) i and iv (B) ii and iii (C) i and ii (D) ii and iv

Read the following statements regarding Gymnosperms:- (A) The main plant body is sporophyte and heterosporous in nature. (B) Roots of some gymnosperms have algal association. (C) The mutilcellular female gametophyte bears two ore more archegonia. (D) The male and female cones may be borne on the same tree or on different trees.

The isotope of U^(238) and U^(235) occur in nature in the ratio 140:1 . Assuming that at the time of earth's formation, they were present in equal ratio, make an estimate of the age of earth. The half lives of U^(238) and U^(235) are 4.5xx10^9 years and 7.13xx10^8 years respectively. Given log_(10)140=2.1461 and log_(10)2=0.3010.