Answer: Option D. -> both a and b
:
D
In organisms like rotifers, honeybees and even some lizards and birds (turkey), the female gamete undergoes development to form new organisms without fertilisation. This phenomenon is called parthenogenesis. Frogs reproduce by external fertilization.

Answer: Option C. -> Juvenile phase - Maturity Phase - Old age
:
C
Life cycle is the period of growth between the birthof an individual up to death. The lifecycle of all organisms involves three phases. They are, in sequence vegetative or juvenile phase, reproductive or maturity phase and senescence or old age.

Answer: Option C. -> Seeds
:
C
Stem cuttings, suckers are the means used for asexual reproduction and the plants formed from these are clones, that is they are identical to each other and to the parent. Seeds are formed due to sexual reproduction in plants and therefore the plants produced are non-identical to the parent plant mother.

Answer: Option D. -> All the above are true
:
D
Internal fertilization is the union of an egg cell with a sperm during sexual reproduction inside the body of a parent. And since the male gamete has to reach the female gamete they are motile and they are large in number so to increase the chances of fertilization. The female gamete is non motile and few in number.

Answer: Option D. -> All of the above
:
D
Spores thus differ from gametes, which are reproductive cells that must fuse in pairs in order to give rise to a new individual. Spores are agents of asexual reproduction, whereas gametes are agents of sexual reproduction. Spores are produced by bacteria, fungi, and green plants.

Answer: Option B. -> Both A and R are correct and R does not explain A
:
B
Monocarpic plants are plants that produce flowers and fruits only once in their lifetime. Most annuals and biennials are monocarpic and produce flowers once in their lifetime, however there are some plants like bamboo and Neelakurinji that have a very long vegetative phase and finally produces flowers and fruits and then perish. But mostperennials are usually polycarpic, that is,they produce flowers and fruits many times in their lifetime.

Answer: Option C. -> Reproduction
:
C
Every organism has a distinct lifespan. Upon completion of this duration, senescence causes the natural death of an organism. Organisms can avoid extinction by theirability to reproduce. So in a way, reproduction enables the continuity of species, generation after generation.
Reproduction does not create exact copies of the parents but usually creates offsprings that share a lot of traits with their parents. The distribution of traits changes due to modification of the genes that produce the offspring. As the distribution of traits changes over time,favourable traits become more and more common, with the environment favouring the organisms with these traits - a process called natural selection. All this diversity and the process of natural selection occur due to reproduction.

Answer: Option D. -> All the above
:
D
Asexual reproduction is also known as Agamogamy/Agmogenesis/Somatogenic reproduction as it doesnot involve the formation and fusion of gametes. It involves somatic cells.

Answer: Option B. -> Viviparous
:
B
In viviparous animals, well developed young ones are born from the female organism at the end of a gestation period. In this scenario, there is no fear of predator and the environmental elements as in case of oviparous animals, that lay eggs and young hatch from it. Viviparous mode of development is not affected by adverse environmental conditions. Therefore the chances of survival of the young one is greater in viviparous animals.

Answer: Option B. -> Tardigrades
:
B
Tardigrades are nature's toughest animals. Earth's most tenacious creatures, which can live in boiling water, solid ice, and the intense radiation of space. It can survive a decade in the desert, without a drop of water to drink, or in the deepest trenches of the sea.