Intercourse between two beings, usually male and female to procreate.
1. Pure substances cannot be separated into any other kinds of matter, while a mixture is a combination of two or more pure substances.
2. A pure substance has constant physical and chemical properties, while mixtures have varying physical and chemical properties (i.e., boiling point and melting point).
3. A pure substance is pure, while a mixture is impure.
1) Well, you need to logically think about which of the pecan trees would be better. Tree 3 may have more clusters but they taste bitter so this is out of the option. So Tree 4 and Tree 1 would be best because they both have rich and buttery tastes and they both have a lot of clusters.
2) Not quite sure about this one, sorry :(