Answer:
The body has levels of organization that build on each other. Cells make up tissues, tissues make up organs, and organs make up organ systems. The function of an organ system depends on the integrated activity of its organs.
Answer:
3 g/mL
Explanation:
We know that the density of an object can be measured by dividing its mass (g) to its volume (mL).
Formula
D=m/v
Given data:
Mass= 45 g
Volume= 15 mL
Now we will put the values in formula:
D=45 g/ 15 mL= 3 g/mL
Answer:
Measuring with a ruler and using final volume minus initial volume
Explanation:
You can measure the volume of a geometric object by measuring its sides with a ruler and calculating the volume according to the corresponding formula for each object. For example, for a rectangular prism it would be

You can also measure the volume of an object by measuring how much water it displaces. To do this you have to fill a measuring cylinder with enough water for the object to be completely submerged and take note of the volume. Then, add the object and note again the volume of the water+object. The difference between both is the volume of the object.

The advantage of the second method is that it can be used for objects with irregular shapes as long as they do not float.
Answer:
2.895*10^24
Explanation:
mass of Oxygen give = 153.9g
molar mass of O2 molecule = 16*2=32g/mol
n= mole
To find the mole
n= mass/ molar mass
n= 153.9/32
n=4.81mol.
To find the number of molecules of o
Nm= number of molecule
Nn = Number of mole
NA = number of Avogados
Nm= Nn * NA
Nm= 4.81 *6.02*10^23
Nm= 2.895*10^24