The three substances that cause a double displacement reaction to occur are:
(i) Ionized compounds. These are usually water.
(ii) A gas that bubbles out a solution.
(iii) A precipitate.
In double displacement reaction is where two new compounds are formed when two parts of two compounds switch places. For example; when sodium chloride combines with silver nitrate, the two new compounds formed are Sodium nitrate and silver chloride reason being sodium and silver switched places.
B. larger and more complex
Explanation: As the environment became more unpredictable, bigger brains helped our ancestors survive.
Cup of boiling water has the higher average, and lake Michigan has the highest total.
Answer:
they have lower levels of the neurotransmitter serotonin
