Answer:
The right answer is B
The development towards 1.4 Ga of eukaryotes, aerobic organisms such as unicellular algae, will be decisive for the oxygenation of the Earth's atmosphere.
The first multicellular organism is a red alga dating back to 1200 Ma during the Mesoproterozoic era (part of Precambrians). Various forms of life with soft bodies dated between 600 and 541 Ma constitute what is called the Vendian fauna, that is to say the fauna of the Ediacarien.
The appearance of a great diversity of small shelly fauna from 541 Ma will mark what is called the Cambrian explosion.
Explanation:
