Science questions in short. [3 marks ]

The fusion of male and female gametes to form zygote is known as fertilization. The process of fertilization takes place in the fallopian tube (oviduct). As sperm enter into the vagina through the process of copulation; it moves upwards and enter into the oviduct. In the oviduct, ovum fuse with the sperm to form zygote.

Cloning is the production of an exact copy of a cell, any other living part, or a complete organism. Yes, gametes are involved in cloning. Dolly and noah are two cloned animals.

Birds are oviparous, i.e. lay eggs outside their body. So, it is easy to collect their eggs and these are thus available in market. On the contrary, dogs are viviparous, i.e. do not lay eggs but give birth to young ones. Their eggs are extremely small which remain inside their bodies.

In vitro fertilization technique is used to help those couples in having babies who can produce sperms and ovum but fertilization does not take place inside the woman’s body due to blocked oviducts.

Both Hydra and Amoeba reproduce asexually involving only single parent but the mode of reproduction is different. Hydra reproduces from bulges or buds arising from the parent body that grows’ and matures into another organism, i.e. by budding, while Amoeba reproduces by binary fission, i.e. splitting of parent organism to form two new organisms.

The zygote divides repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body. This developing structure is termed an embryo. The stage of the embryo in which all the body parts can be identified is called a foetus.

The stages in the life cycle of silkworm occurs in following sequence: This process of transformation from an immature form of an animal to its adult form in two or more distinct stages is called metamorphosis.

In IVF or invitro fertilization technique, is a process by which an egg is fertilized by the sperm outside the body.
The process involves monitoring and stimulating a woman's ovulatory process, removing ovum or ova (egg or eggs) from the woman's ovaries and letting sperm fertilise them in a fluid medium in a laboratory.

Reproduction is one of the important characteristics of living things. The ability of organism to produce young ones of its own kind is called reproduction. It is essential for the continuation of a species.

During fertilisation, only the nuclei of male and female gametes fuse. The sperm reaches to egg and only its nucleus enters the egg cell and fuses with the egg nucleus to form the single-celled structure called zygote. The cell formed consists of only one nucleus but is diploid in nature.

Frog’s eggs are without any external covering or shell but a layer of jelly hold the eggs together, thus providing them protection. This jelly or gelatinous covering also protects them from drying up and prevents them from being eaten up by other animals or predators.

Female fish lay eggs in water while male fish releases its sperms in water. Sperms swim and reach the eggs of fish, randomly due to water currents. When a sperm comes in contact with the viable egg, nuclei of both the cell fuses to form a zygote. This process of fertilisation takes place in water outside the female body, hence fertilisation is external in fishes.

The human male gamete, the sperm has to flow through the female reproductive tract to reach the fallopian tube, where it can fuse with the ovum. Thus, it requires an organ for rapid and efficient motility for transportation. The tail provides this function. The female gamete or the ovum has to travel very little distance, in which it is helped by the ovary and fallopian tube. Thus, it doesn't require any tail.

The type of reproduction in which only a single parent is involved is called asexual reproduction. Binary fission and budding are two methods of asexual reproduction in animals. Amoeba reproduce by binary fission and Hydra reproduce by budding.