<span>The mineral crystals in obsidian are too small to see without a microscope. This is because the rock cools so rapidly from magma that crystals barely have time to form. Obsidian is a normally happening volcanic glass framed as an extrusive molten shake. It is delivered when felsic magma expelled from a well of lava cools quickly with negligible precious stone development.</span>
Answer:
Sharks, in their basal form have been on Earth for hundreds of millions of years. They were the first to develop a stream-like, torpedo shaped body and created a niche for themselves. Their aerodynamic body shape has evolved to allow for efficient and dynamic movement in water. Having a cartilage instead of bones allowed them to grow large and still be relatively light and buoyant . After they've evolved flexible, protruding jaws, there wasn't much to change. They were able to adapt and exploit all the water habitats as the world was changing.
Explanation:
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.
Answer:
The answer is A - The populations will not be able to interbreed because they are different species and different species cannot interbreed
Explanation:
The population of birds become reproductively isolated because they are different species and different species are unable to interbreed. This is as a result of barriers which are called mechanisms of reproductive isolation which involves mechanisms, behaviors and processes that are critical for speciation. In reproductive isolation the different species are able to live in the same are but their properties and characteristics do not allow them interbreed to produce healthy and sterile offspring.
