What do scientist mean when they talk about organisms having a common ancestor?

Based on the data in your tables, did the light-colored moths have a higher or lower survival rate after the industrial revolution?

In tomato plants, mendel found that the allele for smooth seeds (s) is dominant, while the allele for wrinkled seeds (s) is recessive. which of these punnett squares shows crosses between two plants heterozygous for smooth seeds? i need this to be answered as soon as ! sry the picture is bad quality

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.