Answer:
C. four single covalent bonds
Explanation:
Carbon atoms can form four single covalent bonds.
B, Provide nutritional support to the embryo. It is not D, as the breasts are not part of the female reproductive system. It isn't C because during pregnancy, fetal and maternal blood do not mix. It also isn't D since women do not produce sperm.
Answer:
O How can wind be used to generate electricity?
Answer:
Control group remains unchanged.
Explanation:
For example if you are trying to see if watering plants with Pepsi is better.
Your experiment plant would get watered with Pepsi.
Your control plant would get watered with water. (Control groups serve as a reference to compare in the experiment)
