Yes. Oxygen crash led to Cambrian mass extinction
The difference between the time of the heartbeat and the pulse makes the animal Pulse Deficit.
The Atlas. This is the topmost vertebra, and with the axis, it forms a joint that connects the skull to the spine. These two parts of the body (The Atlas and The Axis) are special, and different from normal vertebra, because they are made to allow a greater range of motion and movement in the head. I hope this helps! Also, google is always a helpful tool to use as well. :)
A panther because it eats the primary consumer which would be the deer.
an oak tree is the producer (bottom of the food chain)
the deer is the primary consumer because it eats grass which would also be a producer
and the hawk would be the top predator because it eats a snake which would eat a mouse which would feed on a producer :)
