The composition of lava is the most important characteristic in determining its behavior.
the major compositional groups are:
basaltic lava has low silica contents (~50%) and high eruption temperatures, causing them to flow rapidly and have a low viscosity. basalts flow far from volcanic vents and form broad, sheet-like lava flows.
rhyolitic lava has high silica contents (~70%) and low eruption temperatures, giving them high viscosities. rhyolitic lavas mound up and stay near the volcanic vent because of their resistance to flow.
intermediate lavas, such as andesitic lava, have compositions, temperatures, and volatile contents between those of basalt and rhyolite.
the mineral composition of these groups determines each lava’s prevalence. some minerals melt more readily, leading to larger volumes of lava. basalts and rhyolites are thought to form early and late in the melting process, respectively. more than 90% of the total volume of lava on earth is estimated to be basaltic in composition, while rhyolites make up as little as 1% of the total. andesites and other lavas account for most of the rest.
by considering the compositional group and temperature of lava, we can evaluate the lava’s viscosity and eruptive style.

trachea, alveoli, lung capillaries, arteries

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.

la transducción de señal ocurre cuando una molécula de señalización de fluido extracelular activa un receptor de superficie de la célula.