Chronic bronchitis and emphysema
Answer: Gateway drugs
Explanation: Gateway drugs refers to the fact that the use of a psychoactive drug is associated with a greater probability of using more drugs. The theory about these drugs has been around for a long time. These drugs are easily accessible and may seem harmless to some extent, but they create addictions, leading the person to want to consume something stronger.
Natural active immunity arises from an exposure to antigens, while natural passive immunity <span>arises from the passage of antibodies across the placenta or breast milk. </span>A mother breastfeeding her baby is an example of passive natural immunity.
Passive natural immunity is type of immunity in which antibodies are passed from the mother to fetus or child. In case of breastfeeding antibodies are passes through the breast milk.
Answer:
The correct answer is - Changing PRF.
Explanation:
Pulsed wave Doppler uses the principle of Doppler effect that objects that move changes the characteristic of sound waves. It is creates images by sending the short and quick pulses of the sound, it helps in the determining the velocity of blood in a exact time and location.
PRF or pulse repetition frequencies, is a Doppler sampling frequency that can affect the acoustic exposure of the scanning. PRF is measured in KHz.
Thus, the correct answer is - changing PRF.
