What does the plant do for the nitrogen-fixing bacteria?

Compare and contrast nutrient limitation in soil vs. nutrient limitation in aquatic ecosystems

In sweet pea, gene c is responsible for color production and gene p is responsible for the purple color pigment. both of them are located on two different loci on different chromosomes. the flowers will be purple only when the plant has the genotypes as c_p_. no color will be produced with genotypes: ccpp, ccpp, ccpp, ccpp. thus, gene c controls the expression of gene p. what pattern of inheritance is exhibited here? a. pleiotropy b. epistasis c. multiple alleles

Which of the following explains why a tree is often used as a model to represent the principle of common descent