The fossil record shows a sequence from simple bacteria to more complicated organisms through time, it is very reliable because it is physical evidence and by studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth.
86 % of plants and animals
Answer:
Blood vessels constrict
Explanation:
On seeing danger, impulses are sent to the adrenal medulla. It responds by secreting adrenaline into the bloodstream. This results in the following:
- Increased heartbeat
- Diversion of blood from alimentary canal and skin to skeletal muscles.
- Increased breathing rate and depth
- The liver releases more glucose.
These changes increase energy production especially in the skeletal muscles and prepare animal for sudden fight or flight.
