Answer to Question 1
A
Answer to Question 2
Synchronous rotation is when the rotational period of an object is the same as its orbital period around another object. As an object orbits another, it is stretched by the varying force of gravity across it. The resulting tidal bulges lag behind the rotation of the object slightly and cause it to rotate slower. This continues over time until the rotational period becomes the same as the orbital period, at which point there is no longer any tidal friction and the rotational and orbital periods are synchronized. An example is the Moon always presenting the same face to Earth through its orbit. A variation on this is Mercury which rotates 3 times for every 2 orbits around the Sun.
Much of the dark space between stars, as seen in the sky of the image above, is due to the human eye
A phage cross made by doubly infecting the host cell with parental phages
Charles Darwin may be dead and gone but a recent write-in campaign has pitted him against Republican
Binary Stars
The Spectra of Stars with Different Surface Temperatures.
The Types of Stars and Their Sizes