Which of these BEST summarizes human population growth on the planet Earth? As the dominant Life form on the planet, humans have always existed in

relatively large numbers just like today.

The population of humans on Earth has grown at a slow and steady rate

since the dawn of recorded history to today.

Human population growth on Earth has experienced periods of rapid

increase as well as sharp declines resulting from wars and disease.

Human population growth was gradual for most of the time people have

existed, only in the last two centuries has population growth been rapid.

i don,t know so just answer mine

gas

explanation:

smoke is the matter of a gas

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol