The TTL output stage is a rather complicated pushâpull circuit known as a totem-pole output (the transistors, diode, and resistor in the right-most slice of this TTL logic gate circuit). It sinks currents better than it sources current.
The theory for spontaneous generation refers to the idea that life can produced from nonliving things. Lazzaro Spallanzani proposed in his experiement that air was necessary for spontaneous generation.
Both Bonnet and Spallanzani accepted the preformation theory. According to their version of this theory, the germs of all living things were created by God in the beginning and were encapsulated within the first female of each species.