Sponges and cnidarians exchange substances with the environment directly through the surface of their body. Examples of animals with circulatory systems (open and closed). Cirulatory system in human beings: click here .
Entra en el siguiente enlace para realizar las actividades de repaso correspondientes a la unidad de las plantas: https://www.goconqr.com/quiz/20367442/1-eso-plantas
Insects : Respiratory system of insects: insects exchange gasses through tracheae , very thin tubes which originate at openings in the body called spiracles and extend throughout the body.
Fish . Learn about fish wathing this video. Gills are the respiratory organs in fish. Focus on the picture below: Mammals, reptiles, birds and some amphibians exchange gasses through lungs :
The traits linked to sex are those determined by genes located in the sex chromosomes (X and Y). After watching this video you should know to answer the following questions: 1) What does a trait is linked to sex mean? 2) Why sex-linked traits tend to be on the X chromosome? 3) What is haemophilia? 4) What means that an individual is a carrier?
Nutrition. As you have studied the nutrition is different depending on the animal. In ruminates , such as cows, the digestion takes place in this way. They have four-compartment stomach: rumen, reticulum, omasum and obomasum for taking nutrients from grass.