Consider the following statements regarding double fertilization and choose the correct answer:<br>1. At the time of the sperm's approach to the egg nucleus, the male nucleus has the appearance of a continuous thread rolled into a ball<br>2. It is only the presence of the two nucleoli which serves to distinguish the fertilized egg from the unfertilized egg<br>3. Finally, the male nucleolus increases in size and fuses with the female nucleolus thus closing the phenomenon of sexual union of the nuclei<br>4. The fusion of the male gamete with the secondary nucleus results in the formation of a sister embryo

Consider the following statements regarding recurrent type apomixis and choose the correct answer:
1. There is meiosis during the formation of megaspore
2. The embryo sac is diploid in nature
3. The embryo sac never develops from a cell of the archesporium
4. The development of embryo from a cell of an embryo sac other than egg is known as apospory

A

Only 1, 2 and 3 are true

B

Only 1 and 4 are true

C

Only 2, 3 and 4 are true

D

Only 2 and 4 are true

Consider the following statements regarding the embryological evidences for evolution and choose the correct answer:
1. Algae are much advanced than mosses and ferns
2. Protonema of mosses resemble certain green algae
3. Both bryophytes and pteridophytes have ciliated sperms and require water for fertilization
4. Gymnosperms do not need water for fertilization
5. Cycads and Gingko, the primitive gymnosperms, have ciliated sperms like the pteridophytes

A

Only 2, 3 and 4 are true

B

Only 1, 2, 3 and 4 are true

C

Only 3, 4 and 5 are true

D

Only 2, 3, 4 and 5 are true

Consider the following statements regarding Xenia and choose the correct answer:
1. If a white variety (yy) is pollinated with pollen from a yellow variety (YY), one of the male gametes (Y) will unite with the egg (y) to produce a hybrid embryo (Yy) which will act as a heterozygote for yellow endosperm in the next generation
2. The second male gamete (Y) will unite with the two polar nuclei (y, y) and produces the primary endosperm nucleus (Yyy) which is triploid
3. If a yellow endosperm variety (YY) is crossed with pollen from a white grained variety, the grains produced are white like the pollen parent

A

Only 1 and 2 are true

B

Only 2 and 3 are true

C

Only 1 and 3 are true

D

1, 2 and 3 are true

Consider the following statements and choose the correct answer:
1. For the development of viable seeds the double fertilization is very necessary
2. The net result of double fertilization is the formation of endosperm from the triploid nucleus
3. In Angiosperms very free nuclear divisions take place as in Gymnosperms
4. The endosperm nucleus has both maternal and paternal characters showing physiological importance like hybrid vigour

A

Only 1, 2 and 3 are true

B

Only 2, 3 and 4 are true

C

Only 1, 3 and 4 are true

D

Only 1, 2 and 4 are true

Consider the following statements regarding the origin of polyploidy and choose the correct answer:
1. The egg may be fertilized by more than one sperm
2. There may be a failure of mitosis
3. Triploids may arise as a result of fertilization of unreduced gametes
4. An autotetraploid may arise either by the doubling of chromosomes or fertilization between two different gametes

A

Only 1 is true

B

Only 2 and 3 are true

C

Only 1, 2 and 3 are true

D

1, 2, 3 and 4 are true

Consider the following statements and choose the correct answer:
1. In Oenothera type of monosporic embryo sac, the embryo develops from the micropylar megaspore of the tetrad
2. Antipodal cells are altogether absent in Oenothera type
3. The genus Trapa forms an 8-nucleate embryo sac of the Polygonurn type
4. Oenothera type of embryo sac development has been found to be a characteristic feature of the entire family Onagraceae

A

Only 1, 2 and 3 are true

B

Only 2, 3 and 4 are true

C

Only 1, 2 and 4 are true

D

1, 2, 3 and 4 are true

Consider the following statements regarding the egg (Oosphere) and choose the correct answer:
1. The oosphere contains a female generative cell
2. The upper part of the oosphere membrane is made of cellulose
3. As the maturation of the oosphere nucleus increases its stainability also increases
4. In the cytoplasm of the oosphere, apart from the nucleus certain plastids are also found which manufacture starch found in it

A

Only 1, 2 and 3 are true

B

Only 1, 2 and 4 are true

C

Only 2, 3 and 4 are true

D

Only 1, 3 and 4 are true

Consider the following statements regarding poloyembryony and choose the correct answer:
1. False polyembryony includes the development of two or more embryo sacs within the Same nucellus, and the embryos are derived from different embryo sacs
2. In cleavage polyembryony, the zygote instead of giving rise to one embryo produces embryos by cleavage
3. According to Jeffrey (1895), in Erythronium americanum the "embryogenic mass" forms two or three embryos

A

Only 1 and 2 are true

B

Only 2 and 3 are true

C

Only 3 is true

D

1, 2 and 3 are true

Consider an enclosure formed by three surfaces having the following values of shape factors, emissivities and temperatures Surface 1 i.e. curved cylindrical has an emissivity 0.75 and temperature 800 K Surface 2 i.e. closing disc has an emissivity 0.8 and temperature 700 K Surface 3 i.e. closing disc has an emissivity 0.8 and temperature 700 K The closing flat discs are 25 mm in diameter and they have interspacing distance equal to 100 mm. If the shape factor between these two identical discs is 0.05, calculate the net rate of radiant heat flow from the curve surface to each of the closing end surface

A

1.561 W

B

2.561 W

C

3.561 W

D

4.561 W

Consider the following statements regarding sporogenesis and choose the correct answer:
1. Gametes ape always unicellular and microscopic in size
2. The union of similar gametes is called fertilization
3. The zygote formed as a result of fertilization is called zygospore
4. The seed on germination gives rise to a new plant

A

Only 1, 2 and 3 are true

B

Only 1 and 2 are true

C

Only 3 is true

D

Only 1 and 4 are true