Choose one of the following statements that provides evidence from the fossil record for the cause of the mass extinction at the end of the Mesozoic Era? A. A massive crater off the coast of the Yucatan peninsula is dated to be the same age as the extinction event.
B. The gouges in rock left behind by massive glaciers in the Cenozoic Era are shown to have occurred shortly after the mass extinction occurred.
C. Fossils of certain animal types went extinct while others thrived, showing that the environment underwent very slow changes over time.
D. Fossils of animals became scarce while fossils of plant life became more diverse in the rock strata created during the mass extinction.

(b) which contains higher levels of vitamin b, oranges or spinach?

explanation:

you can eliminate a, c, and d because they are questions based on opinions.

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