Answer:
D. Nuclear fusion begins under high pressure.
Explanation:
A star is a giant astronomical or celestial object that is comprised of a luminous sphere of plasma, binded together by its own gravitational force.
Some of the examples of stars are;
- Sun (closest to the Earth)
Stars are typically made up of two (2) main hot gas, Hydrogen (H) and Helium (He). The chronological order in which the formation of a star occur are;
1. Gravity pulls gas and dust together to form dense cores.
2. A protostar forms as mass increases.
3. Nuclear fusion begins under high pressure.
Hence, the final event that occurs when a star is forming is that nuclear fusion begins under high pressure.
Answer:
Phosphorus is essential for growth of plants and other organisms. When concentration of phosphorus mostly from high breeding rate e.g., pigs, cattle etc. rise in water it causes severe growth of plants and algae as well as phytoplanktons. As a results layers of phosphorus start to release phosphorus as well due to positive gradient. These reactions in water are iron-redox reactions that are crucial for the release of phosphorus.
When too much phosphorus accumulates, it produces a degrading growth feedback in plants, algae and phytoplanktons that then shift toward excessive nitrogen available from fertilizers and cause a flip from P to N. Cynobacteria now dominates and denitrification as well as nitrification takes place simultaneously.
Severe eutrophication induces hypoxia in water that cause a major damage to plants biodiversity in the environment.
D. A duck flies to another pond.
The above sentence is an example of emigration. Emigration refers to moving from one area to another for a long or permanent period. In this instance, a duck is leaving the pond it originally resided in (along a population other ducks) in order to reside in another pond. Therefore, it can be said that the duck "emigrated".
Answer:
the rhythm of heart contractions.
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
1. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
2. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
An electrocardiogram (ECG) provides information about the rhythm of heart contractions.
Additionally, the right atrioventricular valve (AV) also referred to as the tricuspid valve is located on the right dorsal side of the human heart. The right atrioventricular valve (AV) comprises of three (3) leaflets (flaps) which opens and closes in order to allow for the flow of blood from the right atrium of the human heart to the right ventricle. Also, the right atrioventricular valve is saddled with the responsibility of preventing blood from flowing backward in the mammalian heart.
The Correct Answer Is "A - Solar Day"
