Answer:
An atom is the smallest particle in a chemical element that holds its chemical properties. Although in the past it was thought impossible to break an atom, within modern chemistry we know that an atom is composed of subatomic particles, which compose the atomic model:
1) electrons, which have a negative charge, such a small size that it is immeasurable, and a mass much smaller than the other two subatomic particles; 2) protons, which have a positive charge; and 3) neutrons, which have no charge.
The protons and neutrons form a dense and massive atomic nucleus, which is called multipons nuclei. The electrons form a cloud of electrons that surround the nucleus.
Flatworms absorb oxygen by diffusion mechanism through their
skin to the cells in their bodies. Since flatworms do not have a circulatory system,
their bodies' cells are positioned close to the skin to ease the uptake of
oxygen from surrounding fluids or water.
Answer:
When a red blood cell is placed in a hypertonic solution, it contracts as water is drawn out of the cell and into the surrounding solution. If the same blood cell is placed in a hypotonic solution, the blood cell grows in size. Blood cells in isotonic solutions do not shrink or swell.
The reason that blood cells change in size when placed in a solution with different salt concentration is due to the osmosis process. Osmosis causes solutions with high concentrations of salt to draw water from areas with low concentrations of salt.
There are some exceptions to this phenomenon. Blood cells can draw water and explode when placed in hypertonic solution on some special occasions. Some diseases affect the structural integrity of blood cells. Also, when human blood cells are exposed to temperatures close to freezing, they can draw water and explode.
Osmosis is an important phenomenon for living systems. The amount of salt in a given solution exhibits a tendency to diffuse through the environment, eventually resulting in equilibrium. In addition to blood cells, the kidneys function through the use of osmotic principles. The kidneys filter an animal's blood to remove excess salt and balance the amount of water
The best estimate of the population of trout in the lake is 500 individuals.
The low number of tagged trout recaptured may be because the tags slipped off.
This possibility can be reduced if the student used tags that does not slip off easily.
<h3>Mark and recapture method</h3>
The formula for calculating the estimated number of individuals in the population is given as:
where:
- N = estimated Number of individuals in the population
- M = number of individuals captured and Marked
- C = total number Captured the second time (with and without a mark)
- R= number of individuals Recaptured (those with a mark)
Calculating the estimate trout population:
N = (50*40)/4
N = 50
Therefore, the best estimate of the population of trout in the lake is 500 individuals.
The low number of tagged trout recaptured may be because the tags slipped off.
This possibility can be reduced if the student used tags that does not slip off easily.
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