Both are 50%, this is because Rr is dominant in a purple stem and rr is recessive in a green stem. By crossing these plants Rxr= Rr and rxr= rr.
The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
Typically it'd be called spawning or in some cases it could be called "roe".
So either "spawn" or "roe".
Multiply by the power of the eyepiece, usually 10x.
