Which of the following does NOT occur during the embryonic period? The primitive streak appears and begins to form the central nervous system. A blood vessel that will become the heart begins to pulsate. Facial features begin to form. Movements like stretching, yawning, and swallowing begin to occur.

Awater molecule is polar because there is an uneven distribution of these between the oxygen and hydrogen atoms.

Sarah and john are having a discussion on genetic diversity. sarah believes that it happen over a long period of time. john it happens immediately. who is correct? a. sarah is correct because genetic diversity occurs over a long period of time. b. john is correct because genetic diversity occurs immediately. c. both are correct because genetic variation can occur or long period of time. d. neither are correct because genetic diversity occurs over any period of time

Explain why biological control methods are generally environmentally superior to chemical pest control methods.