Answer: Chemical bonds
Explanation: an atom has a positively charged nucleus surrounded by a cloud of electrons.
Dopamine is a chemical that serves as a neurotransmitter that governs the transmission of signal between the neurons (brain cells) through binding to the receptors. This is also referred to "reward hormone" because this is excreted during activities that causes too much excitement or satisfaction.
The severe reduction in this hormone is linked primarily to disease that results from the dissociation of the breakdown of this hormone. This causes muscular paralysis, tremor, slow movement. Further this causes difficulty in movement initiation. This disease described above is the Parkinson's Disease.
<span>The answer to question 20 is C. Lines of latitude run parallel to the equator, appearing horizontal on a globe. The answer to question 18 is B - astronomy is a science that studies celestial bodies, and applies work from astrophysics and planetary science. Question 13's answer is D. Weight is the measure of gravitational force on an object and is measured in Newtons. The answer to question 12 is D. The independent variable is the variable the investigator changes to ascertain how this impacts on the dependant variable. The answer to question 11 is B. The classification of magma as basaltic, andesitic or rhyolitic depends on the percentage of silica it contains. The answer to question 10 is B. The particles in metal are held together by metallic bonds which involve closely packed ions and electrons that are free to move about and conduct electricity. The answer to question 3 is D. There are currently more than 24 GPS satellites in orbit, but this is the number that are operational most of the time. The answer to question 2 is B. The dependent variable is affected by the independent variable - it depends on the independent variable.</span>
Microevolution includes evolution at the population and community level.
