If crossing over did not occur, how could the passing on of physical features be affected?

Crossing over is the process by which genetic variations occur. The homologous chromosomes exchange segments of DNA which allow the genetic variations to occur. If crossing over did not occur then there would be reduced genetic variations. The offsprings will have each chromosome identical to either the male or the female chromosome. Hence, the phenomenon of crossing over and independent assortment both are very important to ensure the genetic variations.  

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands