It's been billions of years since Pangea brook apart. Think of all of the forces that have acted upon those continents since. Erosion from water is a big part. Islands have broken off; earthquakes have shifted continents; glaciers have formed, mountains have formed by continents being smashed together. It wasn't a clean cut. Imagine having week old birthday cake left overs. Already when it was fresh and you cut it, crumbs fell off and the cutting wasn't neat. Now a week later as you're trying to pick up an already cut piece, the frosting is falling off and taking pieces of cake with it and it's crumbling. It isn't a perfect fit because time has altered the shapes of the continents.
Answer:
A. Gas is added to the bladder as the fish's depth increases.
Explanation:
The swim bladder is a gas-filled organ localized in the dorsal region of Osteichthyes (bony fish) that allows them to regulate buoyancy, thus maintaining water depth without swimming. Since the swim bladder localizes in the dorsal region, it also functions as a stabilizing organ. This organ is composed of two sacs whose walls contract and expand in response to water pressure. The swim bladder contains an oval window that enables to adjust buoyancy in order to maintain a constant depth, or to ascend or descend in a wide range of water depths.
Answer:
C) They should send signaling molecules across a small extracellular space.
Explanation:
To send a message to nearby cells, signal molecules only need to cross a small amount of space. Bloodstream (choice A) is used for long-distance communication, choice D is too vague, and choice B is used only for cells that are directly touching each other.
Isotopes
Atoms of the same element; number of protons remain the same, number of neutrons vary. Chemical properties remain the same. Atomic mass varies.
Na sodium with 11 neutrons = atomic mass of 22
With 22 neutrons the mass is 23.
Both have 11 protons in the nucleus.