Answer:
Undergrowth of water plants hypoxia
Low levels of oxygen.
Explanation:
Eutrophication occur when lake or river has adequate nutrients that will encourage the growth of water plants i.e algae which lead to the depletion of dissolved oxygen in the lake. The growth of algae is increased due to availability of carbondioxide or phosphorus or nutrients required for photosynthesis. This result in tainted drinking water,hypoxia and degradation of recreational activities.
Answer
Ventricular systole begins during the <u>isovolumetric contraction </u>phase of the cardiac cycle.
Explanation
1. Ventricular ejection
The forceful expulsion of blood from the ventricles into the aorta and the pulmonary arteries.
2. Isovolumetric contraction
The interval between the closing of the AV valves and the opening of the semilunar valves (aortic and pulmonary valves) is known as isovolumetric contraction. it is the beginig of systole. it is the first chamber systolic event. The myocardial muscle fibers have begun to shorten but have not developed enough pressure in the ventricles to overcome the aortic and pulmonary end-diastolic pressures and open the aortic and pulmonary valves. During this period of muscle fiber contraction, the ventricular volumes do not change.
3. Ventricular filling
In this stage AV valve is opened and the blood that has accumulated in atria flow rapidly into ventricles. The ventricular volume increase rapidly. A third heart sound known as S3 is heared during this stage.
4. Isovolumetric relaxation
It is the beginning of diastole. The AV valve are closed at beginig. The atrium in diastole has been filling with blood on top of the closed AV valve, causing atrial pressure to rise gradually. The pressure in the ventricles continues to drop. Ventricular volume is at a minimum and is ready to be filled again with blood.
Answer:
1) abiotic synthesis of small organic molecules (monomers)
2) joining of monomers into polymers
3) packaging of these molecules into protobionts, droplets with membranes that maintained a distinct internal chemistry
4) origin of self-replicating molecules that eventually made inheritance possible
Explanation:
Answer:
The correct answer is D) Infundibulum
Explanation:
The Infundibulum, also regarded as the Pituitary Stalk is an area of the brain that appears like a v-shaped stem which connects the hypothalamus and the posterior pituitary gland.
It functions as a medium by which hormones are conveyed from the hypothalamus into the pituitary gland, and on to the veins.
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About 88 percent of geologic time is represented by the time span called the precambrian <span>era.</span>
