The eons that make up 90% of Earth's history are the Precambrian eons, which consists of Hadean, Archean, and Proterozoic eons.
Answer:
The correct answer is case control study.
Explanation:
A study in which a comparison is made between the patients carrying the disease with the patients not carrying the disease is known as the case-control study. In the mentioned study, the one carrying the disease is termed as cases, and the one that does not possess the disease is termed as controls.
This form of study is generally done to predict the association between the disease and the risk factor. In case-control studies, only observation is done as no attempt is made to change the course of the condition. The prime objective of the study is to predict the exposure of the risk elements for the individuals present in two groups, that is, controls and cases. This form of study is also called case-referent studies or retrospective studies.
Answer:
Option (B).
Explanation:
Heart is the main pumping organ of the body. The human heart is divided into four chambers that are right atria, right ventricles, left atria and left ventricles.
The left and right ventricles can easily be distinguished on the basis of their thickness. The right ventricle is less thicker than left ventricle. The thickness of right ventricle is 9mm whereas the thickness of left ventricle is around 40mm.
Thus, the correct answer is option (B).
Answer:
A
Explanation:
A meteor is a rock falling from the galaxy and usaully is burning because of the atmosphere.
