Q: The megaspore of a conifer, which is never released from the sporangium, divides by mitosis to produce a:

\textbf{Correct Option B} \textbf{Solution} \bullet Megaspores are also known as macrospores which are present in heterosporous plants. Megaspore gradually germinates to form a female gametophyte which then produces the egg cells. \bullet The ovule which is known as megasporangium is formed due to the reductive division of megaspore. Megaspore undergoes mitotic division in order to form a small female gametophyte which contains archegonia and one egg cell. \bullet The megaspore is never released from the ovule ( megasporangium) because it forms the female gametophyte which develops within the megaspore. \bullet So, the correct option is B.

Question 1

Thallophyta includes:

Accepted Answer

Thallophytes are simple plants without well-differentiated body parts. The plants included in these groups are relatively simple or lower plants. They are usually found in aquatic environments. Algae are the representative members of this group. Some common algae Spirogyra, Chara, Cladophora, etc.So, the correct option is option D.

Question 2

Question 3

Which among the following are the examples of thallophytes?

Accepted Answer

Thallophyta means undifferentiated plant or thallus-like forms with single-celled and non-jacketed reproductive organs and mode of development devoid of an embryo stage. Vascular tissue is absent. True roots, leaves, and stems are also absent. It includes algae e.g, Gelidium, Ulva, Cladophora, Chara, Ulothrix, Rhodella etc. Riccia and Marchantia belong to liverworts under the division of Bryophyta.Thus, the correct answer is option A.

Question 4

Which one of the following is a unicellular algae?

Accepted Answer

Chlamydomonas is a genus of green algae. They are unicellular flagellates, found in stagnant water and in damp soil, in freshwater, seawater, and even in snow as &#34;snow algae&#34;.Two filaments of cytoplasm, flagella, extend from one end, and their whip-like lashings pull the Chlamydomonas through the water and rotate it at the same time. A single, cup-shaped chloroplast occupies the greater part of the cell.Hence the correct option is C.

Question 5

Which of the following is called amphibians of plant kingdom?

Accepted Answer

Algae are commonly found in water and rarely on the land, whereas the bryophytes are land inhabiting plants. However, they still need water for the movement of the male gametes. The bryophytes are thus known as 'amphibians of the plant kingdom'.

Question 6

Sketch and label the figure of the following plant and explain briefly its characteristicsMarchantia

Accepted Answer

Marchantia is a genus belonging to Liverworts of division Bryophyta. The plant body consists of a prostrate thallus with root like structures called rhizoids on the ventral surface for anchorage. The thalli are haploid and dioecious, with the female thallus bearing the archegoniophore and the male thallus bearing the antheridiophore for sexual reproduction. Asexual reproduction takes place by formation of gemmae cups. Vegetative reproduction occurs by fragmentation.

Question 7

In which of the following groups would you place a plant which produces spores and embryos but lacks seeds and vascular tissue?

Accepted Answer

Bryophytes are not vascular plants as the conducting tissues are not xylem and phloem rather they are hydroid and leptoid. All mosses have a sporic (diplohaplontic) life cycle that is oogamous.

Question 8

The first vascular plants were:

Accepted Answer

Vascular plants are those which have well developed vascular tissues, xylem and phloem.A) Algae are simple, thalloid and without vessels.B) Bryophytes have a body more differentiated than algae and have root-like and leaf-like structures but lack proper vessels.C) Pteridophytes are evolutionarily the first plants to develop true vascular tissues, xylem and phloem.D) Angiosperms have true vessels but are not the first plants to possess them.So, the answer is 'Pteridophytes'.

Question 9

Question 10

The gametophytic generation in pteridophytes is commonly called ___________.

Accepted Answer

In ferns, gametophytic generation  is represented by heart-shaped prothallus.

Question 11

The megaspore of a conifer, which is never released from the sporangium, divides by mitosis to produce a:

Accepted Answer

extbf{Correct Option B}   	extbf{Solution} \bullet  Megaspores are also known as macrospores which are present in heterosporous plants. Megaspore gradually germinates to form a female gametophyte which then produces the egg cells. \bullet   The ovule which is known as megasporangium is formed due to the reductive division of megaspore. Megaspore undergoes mitotic division in order to form a small female gametophyte which contains archegonia and one egg cell. \bullet   The megaspore is never released from the ovule ( megasporangium) because it forms the female gametophyte which develops within the megaspore. \bullet   So, the correct option is B.

Question 12

A heterosporous plant is one that:

Accepted Answer

Heterosporous plants are the ones that produces two different type of spores. Spores can be different in shape and size and that's the name heterosporous.It produces two different shaped spores to differentiate between male and female gametophytes. A male gametophyte is known as microspores and a small in size and female gametes are known as megaspores and are larger in size.So, the correct option is 'produces microspores and megaspore giving rise  to separate male and female gametophyte'

Question 13

Select the correct pattern of arrangement of reproductive structures for gymnosperms.

Accepted Answer

Gymnosperms are heterosporous, i.e., produce two different kinds of &#10;spores  the male (microspores) and the female (megaspores). The spores &#10;are borne inside the sporangia. The two types of sporangia &#10;(microsporangia and megasporangia) are borne on special leaf- like &#10;structures called microsporophylls ( =  stamens) and megasporophylls &#10;( =  carpels) respectively. The sporophylls are usually aggregated in &#10;the form of compact structures called cones or strobili. The cones are &#10;generally unisexual, i.e., the male cones are microsporangiate (pollen &#10;cones) and the female cones are megasporangiate (seed cones). So, the correct answer is 'Spores  \rightarrow  Sporangia  \rightarrow  Sporophylls   \rightarrow  Strobili'.

Question 14

You are provided with the seeds of gram, wheat, rice, pumpkin, maize and pea. Classify them whether they are monocot or dicot.

Accepted Answer

extbf{Correct answer:}  Option A 	extbf{Explanation for correct answer:} Option A \bullet  Monocot plants bear seeds with one cotyledon whereas dicot plants bear seeds with two cotyledons. \bullet  As from the list, gram, and pumpkin belongs to dicots. Wheat, rice, maize, and pea belong to monocots.  	extbf{Explanation for incorrect option:} Option B- Gram belongs to dicot. Hence, this option can not be correct.Option C- Wheat belongs to monocots. Hence, this option can not be correct.Option D- Pumpkin belongs to dicot. Hence, this option can not be correct/ 	extbf{Conclusion:}  Number of cotyledons in the seed classify the plant in the category of monocot or dicot.

Question 15

Plants whose seeds have two cotyledons are called:

Accepted Answer

On the basis of the number of cotyledons in seeds, angiosperms are divided into monocots (having one cotyledon) and dicots (having two cotyledons). General characteristics of dicots are:Their seeds have two cotyledons.The leaves of dicotyledons have a network-like arrangement of veins.Dicotyledonous seeds contain an embryonic plant.The flowers of dicotyledons have petals and other parts of the flower are arranged in four or five or six. It may contain flowers with four petals, flowers with five petals, flowers have six petals and the stamens also follow this pattern.The seed is protected by a seed coat. For example, sunflower, rose, etc.

Question 16

Give the differences between monocots and dicots.

Accepted Answer

The differences between monocots and dicots are: (i) Monocots-    (a) Seeds with one cotyledon.    (b) Leaves have parallel venation.     (c) Root system-fibrous.(ii) Dicots-     (a) Seeds with two cotyledons.      (b) Leaves show reticulate venation.      (c) Root system- taproot.

Plant Kingdom