Sample b is the control group because it’s the group not being tested and being kept the same.
These alveoli are the smallest types of lung tissue, and one of the most important. In addition to being the primary means by which oxygen enters and carbon dioxide escapes the bloodstream, these small pouches of air are also the reason why the lungs do not totally collapse when a person breathes out. This is because they contain a cell that secretes a special chemical to lower the surface temperature to prevent lung collapse. The alveoli also contain other cells that secrete chemicals to attack and remove any foreign objects in the lungs, such as dust, dirt and other debris.
In addition to making up alveolar sacs, alveoli also form alveolar ducts. It is estimated that there are more than 300 million alveoli in the human lungs, all of which are located in either alveolar ducts or sacs that are found at the end of the smaller passageways, or bronchioles, in the lungs.
SHORT ANSWER:
Alveolar sacs contain tiny pouches called alveoli, whose primary function is gas diffusion. These clusters of alveoli have thin walls that allow oxygen to pass easily from the lungs into the bloodstream and carbon dioxide to flow from the blood to the lungs so it can exit the body.
Cell
Tissue
Organ
Organ system
Organism
Brain, spinal cord, nerves
The brain controls thought, behavior, emotion, memory, and basic life functions. The brain is also the origin of control over body movement. The spinal cord connects the peripheral nervous system (PNS) to the brain; nerve impulses reaching the spinal cord through sensory neurons are transmitted up into the brain. Nerves primarily involve control and coordination of all parts of the body.
The nervous system interacts with every other organ system. For example the hypothalamus in the brain controls the pituitary gland and tells it when to produce hormones, this shows that the nervous system interacts with the endocrine system.
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Answer:
If a forest fire occurs it will impact a population of birds that nest in those trees because their habitat will be burnt down. This will provoke the birds to find a new habitat which can be hard if the entire forest is burnt down. Additionally resources such as food will be burned down as well.