Answer:
No, there are some organisms that only have one cell, although there are organ systems that are made up of many cells. Not all organisms have organ systems.
Explanation:
For example, the Trichoplax. It is an animal with no organs that is tiny and multicellular, and only feeds on microalgae. A Trichoplax are flat organisms about a millimetre in diameter with no internal structures and typically have two cellular layers. These organisms live in the oceans and seas all around the world but are not necessarily found in their natural habitat, more so in captivity such as a marine aquarium. Trichoplax are found to live in symbiosis with such things as bacteria and others in the oceans and seas.
The number of H atoms in 3(NH₄)₂CrO₄ = 24
<h3>Further explanation </h3>
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
(empirical formula) n = molecular formula
Subscripts in the chemical formula indicate the number of atoms
The compound of 3(NH₄)₂CrO₄ ( 3 molecules of (NH₄)₂CrO₄ ) :
Number of H :

Answer:
This metal could be the aluminium with a specific heat of 
Explanation:
A pie of unknown metal presents a mass (M) of 348 g. This metal is heated using energy (E) of 6.64 kJ and the temperature increases from T1 =24.4 to T2 =43.6°C. We can calculate the specific heat (H) of this metal as follows

We can replace previously presented data in this equation. After simplifying and converting to adequated units, we found that

Finally, the specific heat of this metal is

The aluminium could be the metal, its specific heat is similar to that found in this problem.
Finally, we can conclude that this metal could be the aluminium with a specific heat of 
Answer:
The coefficient of Ca(OH)2 is 1
Explanation:
Step 1: unbalanced equation
Ca(OH)2 + HNO3 → Ca(NO3)2 + H2O
Step 2: Balancing the equation
On the right side we have 2x N (in Ca(NO3)2 ) and 1x N on the left side (in HNO3). To balance the amount of N on both sides, we have to multiply HNO3 by 2.
Ca(OH)2 + 2HNO3 → Ca(NO3)2 + H2O
On the left side we have 4x H (2xH in Ca(OH)2 and 2x H in HNO3), on the right side we have 2x H (in H2O). To balance the amount of H on both sides, we have to multiply H2O on the right side, by 2.
Now the equationis balanced.
Ca(OH)2 + 2HNO3 = Ca(NO3)2 + 2H2O
The coefficient of Ca(OH)2 is 1