Usually, the egg will be implanted between 6 to 12 days of egg retrieval. After five days of embryo transfer, the egg reaches blastocyst stage. For accuracy, you need to county the day of retrieval as day 0.
A motor car engine is an Internal Combustion Engine (ICE). Energy is created by burning either diesel or petrol in a combustion chamber. In such an engine, the energy is transferred from the pistons moving up and down at high speeds. This up-down motion is converted to a rotary motion through the crankshaft and axle.
These don't have such a problem with cold temperatures. So although you might get the chills even thinking about having to get in a freezing car to get to work, your engine is equipped to get up and running the second you need it. That doesn't mean you should put the pedal to the metal as soon as you get in.