The correct answer is B !! Both are interdependent thus forming a mutualistic association !!
As both can not live without each other thus making obligate !!
so They share obligate mutual association !! Go with B !!
Answer:
Carbon remains carbon
Explanation:
An atom of one element does not change into an atom of another element.
That's why A, B, and D are wrong.
The right answer is c. 3 to 10 million
The latest estimates are a bit more precise: there are 8.7 million living species (which is included in the range between 3 and 10 million), 6.5 million on land and 2.2 million in the water. Which is amazing, since there is more sea than land on our planet.
Researchers estimate that there are 7.77 million animal species, only 298,000 plant species and 611,000 species of fungi and molds.
1.The presence of valves 2.the milking action of skeletal muscles 3. the veins as the muscles contract