It is hypothesized that RNA may have evolved before DNA because RNA molecules were the first molecules synthesized by Miller and Urey
are more important to genetic inheritance than DNA
can catalyze a variety of biologically important reactions
are found in more modern cells than are DNA molecules

In a classic experiment using pea shape, mendel conducted two separate genetic crosses. in the first cross the parent plants were “true breeding” for pea shape; one had round peas ( r )and the other had wrinkled (r). the first cross produced a filial 1 generation of all round peas. in the second cross, mendel bred plants from the filial 1 generation. this cross produced different results. out of approximately 1000 plants, about 75% were round and 25% were wrinkled.

Use the phylogenetic tree to the right to determine which statement below is true. organisms a and f are not related. organism e is more closely related to organism b than organism f. organisms c and d are more closely related than organisms a and b. phylogenetic trees

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from