<span>Two atoms of hydrogen and one atom of hydrogen </span>
C) Help with plant defense.
Many species are known to eat many plants, including flowers. To avoid being eaten, thorns in a rose bush help defend itself.
The human reproductive system is different in males and females. When a sperm and egg join, the egg is fertilised and a baby starts to develop. Its mother provides all a baby’s needs until it is born.Fertilisation happens when an egg cell meets with a sperm cell and joins with it. The fertilised egg divides to form a ball of cells called an embryo. The embryo attaches to the lining of the uterus. It begins to develop into a fetus and finally into a baby.The mother’s lifestyle can affect the developing fetus. For example, smoking reduces the amount of oxygen in the bloodstream. This can lead to low birth weight and premature birth (when a baby is born too soon). Drinking alcohol during pregnancy can harm the developing baby’s nervous system, especially its brain.
Birth
It takes about 40 weeks for a baby to develop in the uterus. This time is called gestation. After this, the baby is ready to be born. The cervix relaxes and muscles in the wall of the uterus contract. Waves of muscle contraction push the baby out of the mother's body through the vagina.
B Nucleus
Only Eukaryotes have a nucleus. Prokaryotes have the DNA floating around in cytoplasm.
