Use Sammi's model as an example to explain why cells are the building blocks for human bodies?

Answer and Explanation:

The cell is a basic functional and structural unit of life. All living organisms are made up of cells. The human body contains approximately 100 trillion cells in our blood, skin, nerves, muscles, bones, and brain. Humans have 200 diverse forms of cells that come in different sizes and shapes. Each cell performs a specific function in the human body. There are four main types of cells: nerve cells, muscle cells, epithelial cells, and connective tissue cells. Nerve cells are specific for communication. These cells send signals from the brain to glands and muscles that control functions. Nerve cells receive sensory information is from the skin, the ears, and the eyes and send this information to the brain. Epithelial cells cover the interior of hollow body organs such as digestive organs or blood vessels.  Muscle cells are specific for contraction. The body cannot move without muscles. Connective tissue cells protect against foreign invaders and also provide strength to the body.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation: