Mutualism! The tree provides a home and food for the ants, while the ants protect the tree :)
<u>Answer:</u> The density of substance is 
<u>Explanation:</u>
To calculate density of a substance, we use the equation:

We are given:
Mass of substance = 61.6 g
Volume of substance = 
Putting values in above equation, we get:

Hence, the density of substance is 
Answer: this process is called photosynthesis
When temperature increases pressure also increases.
When temperature decreases pressure decreases.
That is why you have low tire pressure when it’s cold out
To cut this short and for your understanding, ionic bond is formed between metals (mostly right column in periodic table). Covalent bond is formed between non-metals (mostly left column in periodic table). So polar covalent is also a covalent bond but it is polar, which means the shape of molecules are not symmetrical hence maybe an atom in a molecule has most of the electron attracted to it causing itself to be partial negative (since electron are negatively charged) and the other atom has its electron being attracted by others became partial positive. Polar covalent can also be when H atom is binding either to F, O or N (also known as hydrogen bond).