Problem: Two frogs are being examined in a laboratory. Frog X was found in a pond in the forest and has a parasite in it. Frog Y was found just outside the laboratory and is missing one eye. The employees at the lab weren't planning on analyzing any frogs, but when they found the one outside their front door they changed their mind. Given the paragraph above, please answer correctly the following question: Which frog is in a symbiotic relationship?

A: Frog X

Problem: Bill and Bob were two brothers. they were both into physical exercise, but Bill chose weight lifting, and Bob running. Given the paragraph above, please answer correctly the following question: Which brother had fewer muscles contract against a resisting force?

A: Bob

Problem: A group of researches studied the green house gas emissions and their effects on Earth and people during the eighties compared to the twenties. Given the paragraph above, please answer correctly the following question: During which decade did Earth experience an increased concentration of carbon dioxide?

A: eighties

Problem: Microbiologist John is studying the anaerobic organism. He collected two samples of this organism, sample A and sample B. Sample A is an anaerobic organism, and sample B is specifically identified as the Clostridium perfringens obligate anaerobe. To compare these samples to other organisms he collected another microbe that is not an anaerobic organism. He labeled it as sample C. Given the paragraph above, please answer correctly the following question: Which sample would not use oxygen as terminal electron acceptor, sample A or sample C?

A:
sample A