Question

Absence of sexual union and failure of meiosis is called
A. Anisospory
B. Amphimixis
C. Apomixis
D. Anisogamy

Answer 1

Cell division is an important characteristic of cells of multicellular living organisms which gives rise to the body organ systems A cell divides by the process of mitosis and meiosis. Meiosis is a process in which a cell undergoes division to produce four daughter cells each having half the amount of DNA as the parent cell. Meiosis occurs in two phases Meiosis I and Meiosis II.

Complete answer:
The given options are discussed below:
- Anisospory : It is usually seen in bryophytes. When sporangium undergoes meiotic division it results in the production of different sizes of spores. The tetrad formed consist of two small spores which produce male gametophyte and two large spores which produce female gametophyte.
- Amphimixis: It is a type of sexual reproduction. It involves the fusion of male and female gametes which leads to the formation of the zygote. In plants, amphimixis leads to the formation of a fertilized egg.
- Apomixis: It is a type of asexual reproduction. In this, there is an absence of fusion of the gametes but the fertilization of the egg takes place. Or we can say that embryos are formed without the need for fertilization and meiosis.
- Anisogamy: It is a type of sexual reproduction in which both the male and female gametes are of different sizes and forms. Their fusion leads to the production of a new generation. The smaller gamete is considered as a male gamete and the larger gamete is considered as a female gamete. The gametes are flagellated and motile.
So the answer is option (C), ‘Apomixis’.

Note:
- Apomixis and parthenocarpy are types of asexual reproduction. Apomixis is the formation of seed without fertilization whereas parthenocarpy is the formation of fruit without fertilization.
- Polyembryony is a condition where two or more embryos develop from a single fertilized egg.
Types of Apomixis include vegetative apomixis, recurrent and non-recurrent apomixis, apospory, and diplospory.