If there weren't alleles for different traits, but rather only one version of a gene for different traits, how would humans be different?

Plsss > .< compare and contrast the characteristics of flatworms rounds worms and earthworms

How does the nervous system affect the excretory system?

When it is summer at the south pole, a. the northern hemisphere is tilted toward the sun. b. the southern hemisphere is tilted away from the sun. c. the northern hemisphere is tilted away from the sun. d. both the southern and northern hemispheres are tilted toward the sun.