Respiration is the chemical process by which energy is released from organic compounds (food) by living cells.

The nervous system in humans consists of the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS comprises...

Irritability is the ability of a living organism to react to changes in its environment, or stimulus. A stimulus is a detectable change...

Growth is an irreversible change in the size of cells and organisms due to cell division (mitosis) and enlargement. Every living organism...

Fertilization in humans is simply how the two gametes (the sperm and the egg cell) fuse to form the zygote. Before the whole process...

This monthly cycle of changes is known as the menstrual cycle.

In this lesson, we will cover: The basic structures and parts of the male and female reproductive systems The functions of the parts of...

As we said before, the main site of plant reproduction is in the flower. Each flower has small differences based on what suits the plant...

Plants move around materials using two sets of tissues: the xylem and the phloem. The xylem transport water and dissolved mineral ions in...

There are several diagrams and charts that are used to show the inheritance of certain alleles through generations.

Reproduction is the process by which living organisms produce new individual organisms or offspring.

Transport is all about getting materials to where they need to go. In every multi-cellular organism, there exists a set structure of...