Doves are the only birds that drink with their heads down true or false

Why has two different alleles for the same trait?

Which factor that affects biodiversity?

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.