Context and question: Most migrations begin with the birds starting off in a broad front. Often, this front narrows into one or more preferred routes termed flyways. These routes typically follow mountain ranges or coastlines, sometimes rivers, and may take advantage of updrafts and other wind patterns or avoid geographical barriers such as large stretches of open water. The specific routes may be genetically programmed or learned to varying degrees. The routes taken on forward and return migration are often different. A common pattern in North America is clockwise migration, where birds flying North tend to be further West, and flying South tend to shift Eastwards.
What obsticals will migrating birds avoid?
Answer: large stretches of open water
Context and question: For example, consider electronpositron annihilation, in which the rest mass of individual particles is destroyed, but the inertia equivalent of the system of the two particles (its invariant mass) remains (since all energy is associated with mass), and this inertia and invariant mass is carried off by photons which individually are massless, but as a system retain their mass. This is a reversible process the inverse process is called pair creation in which the rest mass of particles is created from energy of two (or more) annihilating photons. In this system the matter (electrons and positrons) is destroyed and changed to non-matter energy (the photons). However, the total system mass and energy do not change during this interaction.
What is it called when the rest mass of individual particles is destroyed but the inertia equivalent of the system of the two particles remains?
Answer: electronpositron annihilation
Context and question: The earliest archaeological artifacts in Iran, like those excavated at the Kashafrud and Ganj Par sites, attest to a human presence in Iran since the Lower Paleolithic era, c. 800,000200,000 BC. Iran's Neanderthal artifacts from the Middle Paleolithic period, c. 200,00040,000 BC, have been found mainly in the Zagros region, at sites such as Warwasi and Yafteh Cave.[page needed] Around 10th to 8th millennium BC, early agricultural communities such as Chogha Golan and Chogha Bonut began to flourish in Iran, as well as Susa and Chogha Mish developing in and around the Zagros region.[page needed]
How long ago were the earliest artifacts from that were evidence of humans in Iran?
Answer:
the Lower Paleolithic era, c. 800,000200,000 BC