The divisions that occur during segmentation are called cleavages, and the cells that form are called blastomers. In the Animal Kingdom, the difference in the quantity and distribution of calf in the egg determines differences in segmentation, the lower the rate of division. Because of this, we can consider two basic types of segmentation: holoblastic or total that occurs in the whole zygote; meroblastic or partial, which occurs only in part of the egg.

The fluid balance in the body is closely linked to the presence and amount of sodium ion in the blood. When we eat salty foods, our blood sodium increases, which causes increased blood tonicity. Nervous centers in the hypothalamus, the thirst centers, detect this increase in tone and produce the sensation of thirst.

It is a disease that appears and disappears on its own from time to time, depending on factors such as stress, tiredness, overexertion, fever, sun exposure, trauma and menstruation. In women, herpes can also be localized to the internal parts of the body. Once infected with the Herpes Simplex virus, the person will remain with the virus in their body forever.

Was this how dogs became best friends of our ancestors? In the Ethiopian plains, wolves and frozen baboons live in peace. While monkeys tolerate wolves walking in the midst of their flock, wolves completely ignore primate cubs that would normally be considered a great meal.

Extremely variable in shape, a complete leaf is formed by a "head", the petiole, and a flat surface with two faces, the limb traversed by ribs. The main function of the leaf is to serve as the site where photosynthesis is performed. In some plants there are modified leaves that perform specialized functions, such as insect trapping leaves of insectivorous plants and cactus thorns.

Many animals have colored substances in their blood or hemolymph called respiratory pigments. These substances are able to combine with oxygen gas, significantly increasing the body's ability to transport this gas. The main respiratory pigments present in animals are hemoglobin and hemocyanin.