Which of the following is considered a gamete?

Which of the following is considered a gamete?

  The esophagus is designated by the number ________________.

Why are bacteria in the human intestines beneficial? 

Which blood vessel has the highest concentration of carbon dioxide? (hint: refer to above heart diagrams, if needed)

Accumulation of cholesterol beneath the inner linings of arteries is called ________________.

Which organ is responsible for detoxification of substances such as alcohol?

A team of scientists is trying to categorize a new life form they believe is an insect. On what criteria will the scientists base their decision on whether or not to classify the creature as an insect? Choose the most accurate answer.

Extra Credit +2 pts (instructor graded) Think: A scientist wants to change the DNA of a sexually reproducing organism and have the new DNA present in every cell of the organism. In order to do this after fertilization, she would change the DNA in which of the following?

High levels of this 2nd messenger keep Cyclin B phosphorylated and inactive.