Reproduction

Step 1: Sperms must move to reach the egg. Step 2: Fluid from accessory glands helps movement and nutrition. Step 3: Without it, sperm function can decrease.

Step 1: Ovulation releases the egg from the ovary. Step 2: Fertilization usually occurs in the fallopian tube. Step 3: If the tube is blocked, gamete fusion becomes difficult.

Step 1: In each cycle the uterus prepares for possible pregnancy. Step 2: Fertilization may form an embryo. Step 3: The thick lining helps implantation and early nourishment.

Step 1: After fertilization, the zygote forms an embryo. Step 2: The embryo must attach to the uterine wall. Step 3: Without attachment, it will not get the support needed for development.

Step 1: The embryo needs nutrients and oxygen from the mother. Step 2: The placenta helps transfer these substances. Step 3: It also helps move wastes from the embryo toward the mother.

Step 1: The uterine lining thickens in preparation for pregnancy. Step 2: If fertilization does not occur, no embryo forms. Step 3: Therefore the lining breaks down and leaves with blood and tissue.

Step 1: First the egg is released from the ovary. Step 2: It may fuse with sperm in the fallopian tube. Step 3: Pregnancy progresses when the embryo implants in the uterus.

Step 1: Chemical messengers become more active during adolescence. Step 2: Reproductive organs begin to mature. Step 3: With maturity, the ability to form gametes develops.

Step 1: Sperm has to reach the egg, so it is small and motile. Step 2: The egg contains more cell material for early development. Step 3: Thus their structures match their functions.

Step 1: A contraceptive pill is meant to prevent pregnancy. Step 2: It does not form a physical barrier against body fluid contact. Step 3: Barrier methods and safe behavior are more useful for disease prevention.

Step 1: A copper device is placed in the uterus. Step 2: It can create unfavorable conditions for sperms. Step 3: This lowers the chance of meeting the egg.

Step 1: Testes produce sperms and male chemical messengers. Step 2: The vas deferens only carries sperms forward. Step 3: Blocking the tube stops transport but does not immediately stop production by testes.

Step 1: The egg enters the fallopian tube from the ovary. Step 2: Fertilization usually occurs in this tube. Step 3: Blocking it prevents gametes from meeting.

Step 1: A condom prevents sperms from reaching the egg. Step 2: It also reduces direct contact of body fluids. Step 3: Therefore it helps prevent unwanted pregnancy and some diseases.

Step 1: Adolescence and reproductive health can involve many misconceptions. Step 2: Correct information reduces both risk and fear. Step 3: It supports hygiene, safety, and respectful behavior.

Step 1: The placenta allows exchange between mother and embryo. Step 2: The embryo receives nutrients and oxygen through it. Step 3: If it fails, embryo growth can be affected.

Step 1: The embryo develops inside the mother's body. Step 2: Waste substances also form in its body. Step 3: The placenta helps send these wastes to the mother's blood for removal.

Step 1: A seed contains an embryo. Step 2: At the start of germination, leaves are not fully functional. Step 3: Stored food provides energy and materials for early growth.

Step 1: Water activates the seed. Step 2: The active embryo needs energy. Step 3: Respiration is needed for energy, and oxygen is required for it.

Step 1: If all seeds fall near the parent, competition for space and nutrients increases. Step 2: Fruits can help disperse seeds far away. Step 3: This improves the chance of survival of young plants.