I’m pretty sure the answer is
↳ To transport materials throughout the body!
Multicellular organisms need a circulatory system to transport substances to and from their cells!
There you go! I hope this helped, if there’s anything just let me know! ☻
<span>Explain the difference between a weak acid and a strong acid according to the Arrhenius theory his question in english</span>
Answer: if this is true or false, then this is false, something that is cold has slow moving particles, fast moving ones generate heat which will make it warm, this object has potential energy not kinetic.
Answer:
answer = 22.5m
Explanation:
using

s= (0²-21²)/2(-9.8)
s= -441/19.6
s= 22.5m
do consider marking as Brainliest if this helped!!
Answer:
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.
Explanation:
Percentage of element in compound :

(a) Urea, 
Molar mass of urea = 60 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(b) Ammonium nitrate, 
Molar mass of ammonium nitrate = 80 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(c) Nitric oxide, NO
Molar mass of nitric oxide = 30 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1

(d) Ammonia, 
Molar mass of ammona = 17 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.