C.

If assertion is true but reason is false

According to Eichler's classification, Plant kingdom is divided into two sub-divisions:

(i) cryptogamae

(ii) phanerogamae.

Cryptogamae is further divided into 3 divisions- thallophyta, bryophyta and pteridophyta. Thallophyta in further divided into 2 classes, algae and fungi. Both of these groups have generally undifferentiated plant body ie, they are not differentiated into true root, stem and leaves, hence they are called thallophyta. Also they are non vascular plants. But algae are chlorophyllous and hence show autotrophic mode of nutrition ie can prepare their own food. But fungi are non- chlorophyllous and cannot prepare their own food. So they are heterotrophic in nature.

A.

If both assertion and reason are true and reason is the correct explanation of assertion

Conifer or Pinus is a heterosporous plant producing mega and microspores inside megasporangium and micro-sporangium respectively. Each microsporangium is  small, sessile and elongated sac like structure having two layered wall. Inside the wall, lie tapetum which is a nourishing layer. Also, inside the cavity, there are large number of dusty and two winged microspores present. On maturity the microsporangium wall bursts from the upper side forming a longitudinal slit. A large number of yellow pollen grains are liberated which are carried by wind due to the presence of wings.

D.

If both assertion and reason are false

Neurospora is commonly called pink /red bread mould or pink mould. It belongs to class Ascomycetes fungi or sac fungi. It is used in experimental genetics as it can be grown easily in a definite medium in laboratory. It is a haploid fungus. It is a heterothallic fungus having positive and negative mycelia and somatic fusion of two halpoid nuclei produce a diploid zygote. The zygote by one meiotic and another mitotic divisions forms 8-nuclei and hence ascospores, a characteristic structure of ascomycetes are produced.

A.

If both assertion and reason are true and reason is the correct explanation of assertion

Heartwood formation occurs spontaneously because it is a genetically programmed process. As a result of continued secondary growth for several years, the older parts of the stem and its old branches have a part of its secondary xylem rendered non - functional. Therfore, heart wood is a modified or non- functional secondary xylem. It is also known as duramen. Sap wood is the functional outer younger rings of secondary xylem. It is also known as alburnum. With the passage of time and addition of new outer rings of secondary xylem due to cambial activity more rings ofthe sap wood are changed into heart wood. This leads to the increase in the thickness of heart wood, whereas the sap wood remains of about the same thickness.

B.

If both assertion and reason are true but reason is not the correct explanation of assertion

Vernalization is coolong of seed during germination in order to accelerate flowering when it is planted. 

In colder countries, there are cereals of 2 physiological types, i.e., winter cereals and spring
cereals. Winter cereals are sown in winter and flower in following summer whereas spring cereals are sown in spring and flower in summer.

If winter cereal are sown in spring, it shows vegetative growth but does not flower unless it receives low temperature of winter. However, they can be converted into spring cereal by providing artificial low temperature treatment, (i.e., springification.)

Some plants requiring low temperature requirement (vernalization) for flowering are Secale cereale (European rye), Triticum vulgare, Brassica oleracea, Beta vulgaris, Apium and Lolium perenne, etc.

Site of vernalization is apical meristem or all the meristematic cells. As a result of vernalization, a flowering hormone called 'vernalin' is formed (reported by Melchers), but venalin has never been isolated. Once a plant is vernalized, it can be devernalized by exposing the plant to temperature of 30C or above. For establishing vernalization, plant should be kept at 20°Cfor 4-5 days.