The branch of biology that deals with the relations of organisms to one another and to their physical surroundings.
B. Two protons and two neutrons
It is caused by the atmosphere of the Earth. It is due of the scattering of light by the atmosphere. When the moon is near the horizon, the moonlight must pass through much more atmosphere than when the moon is directly overhead.
Loss of habitat from human civilizations
A karyotype is an organized profile of a person's chromosomes. Two chromosomes specify sex, XX for female and XY for male. The rest are arranged in pairs, numbered 1 through 22, from largest to smallest. This arrangement helps scientists quickly identify chromosomal alterations that may result in a genetic disorder.