In an experiment, what should be the relationship between the control group and the experimental group? A: They should be different in size
B: They should resemble each other in at least two aspects
C: They should not be similar in any respect
D: They should be identical in all respects except one

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

hope this