Question: Read this and answer the question

The use of the term for the Iranian language family was introduced in 1836 by Christian Lassen. Robert Needham Cust used the term Irano-Aryan in 1878, and Orientalists such as George Abraham Grierson and Max Müller contrasted Irano-Aryan (Iranian) and Indo-Aryan (Indic). Some recent scholarship, primarily in German, has revived this convention.

When was the phrase Irano-Aryan first used?
Answer: 1878
Question: Read this and answer the question

Antigonus then sent his son Demetrius to regain control of Greece. In 307 he took Athens, expelling Demetrius of Phaleron, Cassander's governor, and proclaiming the city free again. Demetrius now turned his attention to Ptolemy, defeating his fleet at the Battle of Salamis and taking control of Cyprus. In the aftermath of this victory, Antigonus took the title of king (basileus) and bestowed it on his son Demetrius Poliorcetes, the rest of the Diadochi soon followed suit. Demetrius continued his campaigns by laying siege to Rhodes and conquering most of Greece in 302, creating a league against Cassander's Macedon.

When did Demetrius take control of Athens?
Answer: 307
Question: Read this and answer the question

Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges.

Hight to ultra-high vacuums removes what obstruction?
Answer:
obstruction of air,