Will mark brainliest. What is the main function of the circulatory system in multicellular organisms? A: to bring oxygen into the lung.

B: to put carbon dioxide into all the blood vessels.

C: to expel waste products from the body.

D: to transport materials through the body.

D: to transport materials through the body.

Explanation:

A: to bring oxygen into the lung. is incorrect because it's respiratory system

B: to put carbon dioxide into all the blood vessels carbon dioxide is exhaled out of the body

C: to expel waste products from the body. is excretory system

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.