To perform this test to check if gold is real, make a light, tiny scratch on the item using a small nail file. Choose a spot that is not noticeable if possible. Use a dropper to apply a small drop of nitric acid to the scratch. If there is no reaction, then the piece is probably made from real gold.
Answer:
A Calorie is equal to 1000 calories.
A Calorie is equal to a kilocalorie
Explanation:
Answer:
Exposure to a virus is closely related to the development of immunity, since the immune system is responsible for creating antibodies in response to the presence of potentially harmful biological agents, such as these viruses.
Explanation:
Viruses are biological agents that can produce diseases when they enter the body of a living being.<u> In response to contact with a virus, the</u><u> immune system</u><u> synthesizes specific </u><u>antibodies</u> to combat the foreign biological agent.
Antibody immunity can be of two types. It is fast when it is mediated by immunoglobulins M (IgM), which attack the virus anywhere, while the late and prolonged response is due to the development of immunoglobulins G (IgG).
An example of immunity to a virus occurs with the exhibition to the virus of the Dengue, that creates permanent immunity to the viral serotype to which an individual is exposed.
The acquired immunity, mediated by antibodies, is the base for the development of vaccines.
Plant cells are specialized for life in a hypotonic environment.
Answer: Option A
<u>Explanation:</u>
A cell which lacks the cell wall, will expand and burst. At the point when set in a hypertonic solution, a cell without a cell wall will lose water to the surrounding, wilt and presumably die.
In a hypertonic arrangement, a cell with a cell divider will lose water as well. The plasma layer pulls from the cell wall as it withers, a procedure called plasmolysis. Thus it can be inferred that plant cell are specialized for life in a hypotonic environment.
