Flowers and Plant Reproduction - Class VIII

Many flowers produce nectar, a sugary liquid that many insects eat. When an insect lands on a flower to feed, pollen grains stick to its body. As the insect moves to another flower of the same species, these pollen grains are transferred to the flower's stigma and pollination occurs. After pollination, the plants produce fruits.

Entomophily is a form of pollination whereby pollen or spores are distributed by insects. These plants attract insects with vibrant colours and pleasant odour.

Yucca plant has developed an obligate symbiotic relationship with a moth called Tagetecula, in relation to pollination. Neither the yucca or the moth can survive without the other. The moth’s larvae depend on the seeds of the yucca plant for food, and the yucca plant can only be pollinated by the moth. 

Sweet potato is a root tuber, not a flower; Castor has endospermic seeds; Vallisneria is dioecious; Zostera is marine and exhibits epi-hydrophily. The pair A and D contains errors.

Unisexual flowers only have either the gynoecium or the androecium. Example of unisexual flowers are : Coconut, Papaya, Watermelon.

Bisexual flowers are common in many inflorescences. Raceme and catkins are types of inflorescences where bisexual flowers are frequently found.

 A flower that possesses either stamens or carpels but not both. are called a unisexual flower. coconut, maize, and papaya are unisexual flowers because at their development stage they either posses stamen or carpels. so, 'the correct option is Gulmohar'.

Monecious Plants (mono meaning one) have male and female reproductive organs on the same plant. In other words, they are hermaphrodites. The organs may or may not be on the same flower (i.e. the flowers can be perfect or imperfect. Eg. Coconut, cucurbits, chara, etc. 

Dioecious Plants (di meaning two) have either male OR female flowers (not both). As a result, plants are either male OR female. Imperfect flowers only. Eg. Papaya, cannabis, etc. 

So, the correct option is 'Papaya'. 

1. A flower that lacks one or two of the four whorls is an incomplete flower.
2. A complete flower has all four whorls calyx, corolla, stamens, and pistil are present.
3. A unisexual flower has one of the reproductive organ either stamen or pistil is present.
4. Homosexual flowers are not probable

A flower has four different whorls has calyx, corolla, stamen (male part) and pistil (female part) and if both reproductive parts are present in a flower than it is considered to be a complete flower.

• A unisexual flower is a flower that possesses either stamens or carpels. Cyathium looks like a single flower. 
• It has a cup-shaped involucre formed by bracts encloses a single female flower and a number of male flowers.  
• Thus it has unisexual flowers with each male flower are as a single stamen while a single pistil represents a female flower. 
• Also, it is a type of cymose inflorescence. Other options are not as unisexual.
• The correct option is A.

A bisexual flower is a flower that contains all the four whorls such as petals, sepals, the male reproductive structure (stamen) and female reproductive structure (pistil). Hence it is also called as a complete or perfect flower. Thus the correct answer is 'Four'.

The whorl of the flower are differentiated into two categories essential and non-essential whorl and are consists of 

Carpels, pistil or gynoecium are the female reproductive part of the flower that consists of a stigma that holds the pollen grains, a style that leads the path of pollen tube and ovary produce ovum (female gamete). The flower that has the only pistil is referred to as female flower.

Cleistogamous flowers (that do not open at all) always exhibit autogamy, whereas chasmogamous flowers(with exposed anthers and stigma) can exhibit autogamy, geitonogamy or xenogamy.

Stamens or androecium are the male reproductive part  contains filament which is aslender stalk and anther is bilobed and responsible for the production of pollen grains (male gamete).The flower with stamens is referred to as male flower.

In flowering plants, the unisexual male flower is staminate, i.e., bearing stamens, while the female flower is pistillate i.e., bearing pistils. In some flowering plants, both, and female may be present on same individual (monoecious) or on separate individuals (dioecious).

1. Mucor mucedo is homothallic (self-compatible ) fungi.
2. China rose or Hibiscus flower has both stamen and pistil present on the same plant so it bears a bisexual flower.
3. In Marchantia is a liverwort in which male and female are born on different plants so it is dioecious bryophyte.

When a soaked seed is pressed the water comes out from the pore of the seed which is known as the micropyle.

Roots system develops from the radicle of the embryo because in seed, the radicle grows downward into the soil to absorb water and nutrients from the soil.

The flowers wherein both the sex-organs, that is, the stamen and the pistil are present is called the bisexual or the hermaphroditic flowers. Those flowers wherein, only one of the sex-organ is present and the other is rudimentary absent, are called uni-sexual flowers. These can be pistillate when only pistil is present and can be staminate when only stamen is present.

• Hibiscus, Rose, and Datura have bisexual flowers with both stamens and carpel.
• Papaya has unisexual flowers, male flowers, and female flowers are on separate plants.
• So, the correct answer is 'Papaya'.