Explanation:
Cave lions, sabre-toothed cats, cave bears, giant deer, woolly rhinoceroses, and woolly mammoths were prevailing species of the Quaternary period. Without the dinosaurs, plant life had an opportunity to flourish during the Cenozoic era.
The macronucleus is the larger elipse-shaped nucleus and takes care of
functions like respiration and digestion. In contrast to this, the
smaller micronucleus is only involved in cell division or reproduction.
Oxygen is needed for the heart to oxygenate blood.
Any three characteristics of bacteria area
- lack of membrane-bound organelles
- unicellular
- small (usually microscopic) size.