If no pregnancy occurs, the corpus luteum is reabsorbed into the ovary after two weeks and the hormone levels drop; this causes menstruation.
1) One way is through radiographs. Scientists have studied the spectrum that distant nebulas give off and they have managed to identify molecules that can be found in there. Among them there is hydrogen and various nitrogen and carbon molecules; even alcohol has been found some of them. Another way is by sending probes to asteroids that check not only for simple organic molecules but also aminoacids and nucleotides. A third way was the Urey Miller experiment. There, some basic atoms that can be found in space (nitrogen, hydrogen and carbon) where put together with a spark in a flask. The mixture turned brown and produced complex organic molecules quite soon. This finding makes a case for complex organic molecules being produced in space and thus it is possible that they were transferred to Earth.
2) Geothermal vents are a source of hot water and raw nutrients such as sulphur. The main theory about the genesis of life around vents is that the cells started exploiting the pH or the thermal gradient near those vents and thus had a way to produce energy. The experimental set up for this is a chemical garden, an environment that simulates those alkaline and metallic conditions and yields hollow, plant-like structures. Also some metals in the vents are great catalysts for chemical reactions in organisms. Also fossilised microbes have been found beneath such vents.
Answer:
Two-thirds majority in each chamber.
Explanation:
A president can be defined as an individual who is duly elected by the electorates and as such is the head of the country in a democratic government. The president is empowered by the constitution to sign (veto) legislations, adjourn or convene the legislative body (Congress), grant state pardons and reprieve to citizens, command the armed forces, and welcome ambassadors representing other countries.
In the United States of America, the president has various powers granted by Acts of Congress and Article II of the U.S constitution such as Ordinance power, Appointment power, Implied power, Executive power etc.
Hence, by virtue of an executive power, the president is empowered to issue an executive order such as a decree, instructions, regulations and rules in order to successfully manage the affairs of the country and good governance.
To override a presidential veto, congress must vote at a minimum by two-thirds majority in each chamber (upper house and lower house). The upper chamber or house consists of senators while the lower chamber consists of house of representatives.
Gregor Mendel was the "father of modern genetics" and helped disprove the blended theory of inheritance.