Which sentence uses commas correctly? Carl could rope ride and herd for the ranch. Carl could rope, ride, and herd for the ranch.
When a dairy farmer chooses to breed the cows that give the most milk in the herd, the farmers are following the principle of: A. artificial selection. B. acquired characteristics. C. descent with modification. D. natural selection.
So, the number of ways is which 30 competitors from 50 can qualify is given by the formula of combinations, which is:
C (m,n) = m! / (n! * (m -n)! )
=> C (50,30) = 50! / (30! (50 – 30)! ) = (50!) / [30! (50 – 30)!] = 50! / [30! 20!] =
= 47,129,212,243,960 different ways the qualifiying round of 30 competitors can be selected from the 50 competitors.
Three ways that the circulatory system and respiratory system are protected: The cutaneous system, the thoracic cage, and the immune system.
The cutaneous system:
The skin is the largest organ of the body and is the external interface with the external environment.
==> In its role of barrier, the skin ensures:
* physical and immune protection against external aggressions (microorganisms, foreign substances, traumas),
* protection against U.V. radiations,
* protection against liquid losses of organisms living in an open-air environment,
* protection against the cold (hypodermic fat layer and organized hairs in fur).
==> It participates in the thermoregulation of the body by:
evaporation mechanisms provided by eccrine sweat glands,
radiation mechanisms ensured by an organized vascular system in anastomotic plexuses supplemented with arteriovenous shunts.
The rib cage has a protective role for internal organs: Due to its shape and constitution, the rib cage protects vital organs such as the heart and lungs, as well as certain abdominal organs.
It also has other roles:
Role of mobility. Its constitution, partly cartilaginous, gives it a flexible structure to follow the movements of the spine.
Role in breathing. The flexible structure of the cage, as well as the various articulations, gives him large amplitudes of movements, participating in respiratory mechanics. Various breathing muscles also sit on the rib cage.
Set of cells whose role is to defend the body (including the circulatory and respiratory system) against infections.
The immune system’s role is to defend the body against infections. When it is invaded by a foreign organism (virus, bacteria) or by foreign molecules (pollen, for example), the immune system reacts very quickly to get rid of it. Unlike other systems, the immune system consists of isolated cells that are not tissue.
The lungs represent the largest epithelial surface of the organism exposed to the external environment. During respiration, the airways and pulmonary alveoli are constantly in contact with a multitude of particles and microorganisms conveyed by the air flow and sometimes deposited on the surface of the tracheobronchial tree.
Unlike other epithelial surfaces such as the skin or the digestive tract, the cells are sterile.
This phenomenon results from a complex system of, particularly effective defenses. These are anatomical features of the respiratory tract and the defense system.
The blood in the circulatory system ensures the defense of the body (thanks to the cells of immunity) including the blood itself.