Answer:
The correct answers are:
1. closing
2. the ventricles and arteries,
3. a constricted trachea
Lub is the first sound of a heartbeat and is mentioned as S1. It is usually produced due to the closing of tricuspid and and mitral or bicuspid valves present between atria and ventricles.
Tricupsid is located between atrium and ventricle of the right hand side and mitral valve is located between atrium and ventricle of the left hand side. They prevent the back flow of blood from ventricles to their respective atria.
Dub, being the second sound is written as S2. It is produced due to the closing of pulmonary (located between right ventricle and pulmonary artery) and aortic valves (located between left artery and aorta).
These valves prevent the back flow of blood from arteries into the ventricles.
The time between the two sounds is often taken as the measure of the diastole i.e. ventricular filling.
Wheezing refers to a high-pitched sound produced when a person breathes, especially during exhale. It is caused by constriction of the airways or inflammation. It is considered as a symptom of various diseases such as asthma, COPD, allergies, bronchitis etc.
Answer:
Water
Explanation:
Its water because water has many forms and all those forms are being converted into other forms of water during the cycle
Answer:
mitochondria serve as the power house of a cell.
The right answer is Scientists should conduct long-term studies of DNA technology to determine the consequences.
DDT is a potent insecticide: it kills by opening the sodium channels of insect neurons, destroying them instantly, leading to spasms and then death. Some genetic mutations acting on the sodium channels can make some insects resistant to DDT and other insecticides working on the same principle.
The US Environmental Protection Agency has categorized DDT into the B2 class, that is, potential carcinogen for humans. This supports the fact that the insecticide acts on human DNA.
