The earliest photosynthetic organisms on Earth likely used an alternative electron source during photosynthesis. What electron source did they use?

Which of the following are accessory pigments that act as secondary light collectors during photosynthesis, to help prevent the formation of reactive oxygen species in the cell?  

Which molecule is produced when PEP carboxylase fixes CO₂ in C4 plants?

When performing 5 repeats of 10-fold cross validation to compare two architectures, why is the standard t-test generally considered inappropriate for evaluating the final results?

Model X achieves an accuracy of 0.75 on a test set of 300 instances. Model Y achieves the same accuracy on a test set of size 3,000. Which model has a more reliable / precise estimate of true accuracy?

Given the ROC curves in the Figure below for algorithms A and B, indicate which algorithm you would use if your target true positive rate is 0.8, and which you would use if your target true positive rate is 0.2 (in that order).  

Which of the following is NOT true for K-means clustering?

Compared to decision trees, Rule-based classifiers typically have a [choice1] hypothesis search space , but are often favored because their models are generally [choice2] interpretable.

Association Rule mining

You are asked to classify a dataset into 4 separate categories. If you are only allowed to use a standard, binary logistic regression, how can this task be accomplished?