Which mixture of gases is thought to have made up earth's early atmosphere? a. methane, oxygen, hydrogen, water vapor b. carbon dioxide, nitrogen, oxygen, ozone c. hydrogen, water vapor, ammonia, methane, carbon dioxide d. ozone, water vapor, carbon dioxide, ammonia

An example of what is geese flying south for the

Apea plant that is heterozygous for the tall phenotype can produce short offspring when self pollinating. which of the following explains why this occurs? a. segregation of allels b. condominance of traits c. polygenic expression of traits d. independent assortment of alleles

Which of the following structures is not found in both plant and animal cells? a) chloroplast b) cytoskeleton c) ribosomes d) mitochondria