Infants between the ages of six and 12 months are especially at high risk for contracting measles because they are too young to
receive the vaccine. Infants are often protected until they are about 6- months-old by maternal antibody. Their mothers either had measles, or were vaccinated against it, before they became pregnant, but as these babies get older, that protection fades. Which of the following is the maternal antibody that protects infants for the first six months of life? a. IgA
b. IgD
c. IgE
d. IgG
e. IgM
During pregnancy the fetus is attached to the mother body by placenta and IgG is the only antibody which can cross the placenta and reach the fetus. This antibody is very important for an infant to get protection from infections.
Measles is a viral disease that usually infects infants who are not vaccinated against it. Until the vaccination is done the infant is protected by the passive immunity given by his mother through passing the IgG antibody.
This maternal antibody is capable of protecting infants for the first six months of life after which vaccination is required to protect the infant from measles.
The human ear can easily detect frequencies between 20 Hz and 20 kHz. Hence, sound waves with frequency ranging from 20 Hz to 20 kHz is known are audible sound. The human ear is sensitive to every minute pressure difference in the air if they are in the audible frequency range.
Yes. Upper-layer skin cells and the cells in the front surface of the eyes get a significant amount of oxygen directly from the air rather than from the blood. Human bodies have a huge demand for oxygen. As a result, the oxygen that is able to passively diffuse into the body directly from the air is not nearly enough to run the whole body. Fortunately, we have lungs that can actively pull in oxygen and transfer it to the blood, allowing the body to transport oxygen to the cells by using the blood like a fleet of delivery trucks. Most of our cells rely on the blood delivery service. However, the cells in the outer layers or our skin and eyes are in direct contact with the atmosphere and can efficiently get their oxygen right from the air.
Yes, there are nuclear reactions constantly occurring in our bodies, but there are very few of them compared to the chemical reactions, and they do not affect our bodies much. All physical objects are made of molecules. A molecule is a series of atoms linked together by chemical (electromagnetic) bonds.
Photon wave phase can also not be directly detected by humans but can be detected by machines called interferometers. Phase information is often used to determine the flatness of a reflecting surface. In summary, humans can indeed see photons. Humans can see all of the properties of photons except for spin and wave phase.