Answer:
The hardness rating is 4.
Explanation:
Calcite sits at a hardness rating of 3 and is very easily scratched with a knife and/copper coin. This is where most Marbles, limestones, travertines, rate.
Meanwhile, Fluorite sits at hardness 4 and can be scratched by a knife.
What is different with retroviruses in reproduction is that they do not kill their hosts at first because they can still insert their own genome. This process is what is known the reverse transcription. This is done by different proteins.
Answer: They help control what enters and leaves the cell.
Explanation: carbohydrates also help the immune system identify if the cell is foreign or not.
Answer: option A - threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems
Explanation:
Invasive species refers to organisms that appears at a particular habitat that has just undergone an environmental unfavorable condition.
These INVASIVE SPECIES poses THREAT to the native organisms, because they usually possess:
better resistance to disease,
higher reproductive rate, etc.
So, even when native organisms migrate or dies, Invasive species REMAINS. As a result, they threaten the maintenance of a biologically diverse ecosystem
"Their habitats may range from the surface water to the ocean trenches. Marine organisms are classified<span> by how they move and where they live."
Hope This somehow helps~
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