A molecule of H2o or Water
Answer:
Jonas Salk was awarded the Nobel Prize for discovering a way to vaccinate against polio in the United States in the 1950's. This allowed millions of school-age children to avoid crippling disease, and to swim during summer again, as polio was often spread in public swimming areas before.
The statement that best describes how the polio vaccine works is:
It triggers the immune system to produce antobodies to fight the disease-causing agent.
Explanation:
There are two main reasons for this answer. The first one is that every vaccine is aimed to introduce a controlled amount of antigenes to be accepted by the organism. These antigens are made after some studies were conducted in a lab and were obtained from substances that the human body can accept to train the immune system to develop an effective defense for the virus or bacteria on the matter. In our case, the polio vaccine works the same way and allowed to save many lives.
Answer:
the moon orbit earth every 27.3 days ,while the earth orbit the sun every 365 .25 days .
Explanation:
<h3><u>Answer and explanation;</u></h3>
- Density plays an important role in the study of Earth. It affects Earth's climate, plate tectonics, and subduction.
- <em><u>Subduction occurs at the convergent plate boundaries. Density plays a major role for subduction to take place. Subduction is driven by the excess density of the lithosphere compared to the underlying asthenosphere.</u></em>
- <em><u>Oceanic plates are denser and colder than continental plates, because the ocean cools them. Subduction can occur between an oceanic plate and a continental plate, or two oceanic plate or two continenetal plates.</u></em>
- During subduction between oceanic and continental plates, mantle convection drags the denser oceanic plate downwards and forces it down into the asthenosphere.
- During subduction between two oceanic plates, mantle convection drags the older, denser oceanic plate downwards and forces it into the asthenosphere.
- During subduction between two continental plates, there is no mantle convection, because the two plates are of similar densities.
