Hint:Asexual reproduction is the type in which the offspring arise from a single cell or from a multi-cellular organism, and inherit the genes of that parent. It is the main form of reproduction in single-celled organisms such as archaea and bacteria.
Complete answer: Many multicellular animals, plants and fungi can also reproduce asexually.It does not involve the fusion of gametes or change in the number of chromosomes, hence, the offspring is the exact copy of the parent. A mate is not required in this case. The different types of asexual reproduction are binary fission, spore formation, fragmentation, parthenogenesis, budding, vegetative propagation and apomixis.
The offspring can be produced more quickly and relatively more straightforward than in the sexuals. It skips the courtship rituals as seen in higher forms of sexual animals. A large number of offspring can be produced within a short span of time. Mobility is also not required for the organism to produce daughter cells. This process of reproducing is not complex, which only requires less energy compared with its counterpart.Hence, the time and energy required is very less compared to sexual beings.
There are also many disadvantages to it like, lack of genetic diversity. Unlike in sexuals that involves recombination and segregation during meiosis and the fusion of the sex cells with different genetic materials, asexuals do not go through these processes. Absence of meiotic events could lead to low genetic variation, and therefore, may cause long-term evolutionary disadvantages. Unfavorable mutations or environmental conditions can make the asexually produced organisms prone to diseases and a huge number of offspring could be destroyed. It can also lead to their extinction.
Hence, the correct answer is option B, ‘Lack of genetic variation’.
Note:Asexual reproduction is less costly in terms of energy and time expenditure. Though asexual reproduction can occur in various types of environment, any type of change can lead to their destruction.