Leeches are parasitic because they suck blood not giving any benifit but harm.
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.
The statement in the given question that presents a condition of the Hardy-Weinberg principle is that random mating occurs. The correct option among all the options given in the question is option "C".
There are definitely certain
conditions under which the Hardy- Weinberg principle occurs and they are when
there is no gene flow, no mutations happen, no generic drift occurs and random
mating occurs. This principle also states a very important aspect and it is
that genotype and allele frequencies will always remain constant from one
generation to another if there is absence of other evolutionary inflrnce.
