QUES: The avian circulatory system is driven by a four-chambered, myogenic heart contained in a fibrous pericardial sac. This pericardial sac is filled with a serous fluid for lubrication. The heart itself is divided into a right and left half, each with an atrium and ventricle. The atrium and ventricles of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. Being myogenic, the heart's pace is maintained by pacemaker cells found in the sinoatrial node, located on the right atrium. The sinoatrial node uses calcium to cause a depolarizing signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to the ventricles. The avian heart also consists of muscular arches that are made up of thick bundles of muscular layers. Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood throughout the body. Avian hearts are generally larger than mammalian hearts when compared to body mass. This adaptation allows more blood to be pumped to meet the high metabolic need associated with flight.

Where is the heart contained in the avian circulatory system?
What is the answer?
ANS: fibrous pericardial sac
QUES: In astronomy, Muḥammad ibn Jābir al-Ḥarrānī al-Battānī improved the precision of the measurement of the precession of the Earth's axis. The corrections made to the geocentric model by al-Battani, Averroes, Nasir al-Din al-Tusi, Mu'ayyad al-Din al-'Urdi and Ibn al-Shatir were later incorporated into the Copernican heliocentric model. Heliocentric theories were also discussed by several other Muslim astronomers such as Al-Biruni, Al-Sijzi, Qotb al-Din Shirazi, and Najm al-Dīn al-Qazwīnī al-Kātibī. The astrolabe, though originally developed by the Greeks, was perfected by Islamic astronomers and engineers, and was subsequently brought to Europe.

What work is Muḥammad ibn Jābir al-Ḥarrānī al-Battānī known for as it regards to earth?
What is the answer?
ANS: improved the precision of the measurement of the precession of the Earth's axis
QUES: Because of the general instability of the federal government during 1828, the installation of the new legislature did not take place until the middle of the following year. It was quickly dissolved by Governor Santiago de Baca Ortiz, who replaced it with a more pronounced Yorkino type. When Guerrero's liberal administration was overthrown in December, Gaspar de Ochoa aligned with Anastasio Bustamante, and in February 1830, organized an opposition group that arrested the new governor, F. Elorriaga, along with other prominent Yorkinos. He then summoned the legislature, which had been dissolved by Baca. The civil and military authorities were now headed by J. A. Pescador and Simón Ochoa.

Which new governor was arrested by Ochoa and Bustamente?
What is the answer?
ANS:
F. Elorriaga