Which part of your integumentary system is found on the outside of your body? * a. Epidermis

b. Keratin

c. Dermis

d. Melanin

The correct answer is a. Epidermis.  

Explanation:

The skin is made up of two layers that have different structure and origin: epidermis and dermis, which are closely related. The epidermis is the most superficial part of the skin and is made up of a keratinized flat stratified epithelial tissue, where several layers or strata can be seen that, depending on their greater or lesser development, allow the skin to be classified into thick and thin. The thick skin is on the palms of the hands and the soles of the feet and is characterized by a thick layer of keratin and by having a so-called lucid layer that does not exist in thin skin. Thin skin also has keratin, but the thickness of the keratin layer is much less. The epidermis is separated from the dermis by a limiting membrane, the basement membrane, which measures 50-70mm thick and is attached to the dermis by reticular fibrils that show axial periodicity.

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:

creative diagnostics provides a protocol for total protein extraction based on ripa which is widely used.