Railway Science (Biology-Reproduction in Animals) (Part-II)

Salpingostomy is also done when the end of the fallopian tube is blocked by a buildup of fluid. This procedure creates a new opening in the part of the tube closest to the ovary.
But it's common for scar tissue to regrow after a salpingostomy. This can reblock the tube. Intrauterine devices or IUDs are small T-shaped devices that are planted in the uterus.
There are two types of IUDs. Copper IUD - Releases small amounts of copper in the uterus which prevents sperms from reaching the ovary. Hormonal IUD - Releases progestin in the body which prevents the formulation of eggs.
Condoms are a "barrier" method of contraception. They are made of very thin latex (rubber), polyurethane or polyisoprene and are designed to prevent pregnancy by stopping sperm from meeting an egg.

Four Stages in the life cycle of a butterfly → Stage One (lasts for about a week) : Egg - The adult butterfly lays her eggs safely on a leaf. Stage Two (last between twelve and fourteen days) :
Larva - The egg begins to hatch and a caterpillar is revealed. Stage Three (lasts for about a week) : Pupa - The caterpillar forms a protective chrysalis that protects it from the outside world while allowing it to undergo important changes.
Stage Four : Butterfly - The caterpillar has gone through a metamorphosis, which is a change from one physical form to another, and emerges from the chrysalis as a butterfly.

Autosome - It is any chromosome that is not a sex chromosome. In humans, each cell normally contains 23 pairs of chromosomes. Twenty-two of these pairs are called autosomes and look the same in both males and females. The 23rd pair is called the sex chromosomes, which determines sex of male and female.

Zygote - It is created when the sperm and egg combine. Blastocyst - A cluster of dividing cells made by a fertilized egg. It's the early stage of an embryo. Embryo - An initial stage of development of a multicellular organism. Fetus (foetus) - An unborn offspring that develops from an animal embryo.

In humans, the sex of an individual is determined by the presence or absence of certain sex chromosomes. There are 23 pairs of chromosomes in humans. Males have one X and one Y chromosome (XY). XY sets of chromosomes lead to the birth of a boy child.

If the copies are not identical, the trait that gets expressed is called the dominant trait and the other is called the recessive trait. Variations arising during the process of reproduction can be inherited. These variations may lead to increased survival of the individuals.

Binary Fission in organisms can occur in four ways. Irregular fission involves cytokinesis taking place along any plane but always perpendicular to the plane of karyokinesis (nuclear division). Example - amoeba. Longitudinal fission occurs along the longitudinal axis. Example - In flagellates like Euglena. Transverse fission occurs when an organism divides into two individuals along the transverse plane. Example - In ciliated protozoans like Paramecium. Oblique : In this type of binary fission cytokinesis occurs obliquely. Example - Ceratium.

A child's biological sex determination (male or female) is on the basis of the chromosome that the parent contributes. Males have XY sex chromosomes while females have XX sex chromosomes; the male can contribute the X or Y chromosome, while the female contributes one of their X chromosomes.

Female gametes are called ova (egg cells), and male gametes are called sperm. Lymphocytes - White blood cells that are also one of the body's main types of immune cells. They are made in the bone marrow and found in the blood and lymph tissue.
Red Blood Cells (Erythrocytes) - It plays an important role in the transport of oxygen and has a lifespan of 120 days. White Blood Cells (Leukocytes) - They are colourless. Responsible for fighting against infection causing organisms inside the body.

Homologous chromosome pertains with the same gene sequence, loci, chromosomal length, and centromere location. In humans, each cell normally contains 23 pairs of chromosomes.
22 of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have XX chromosomes, while males have one XY chromosome.