The fossil evidence found in these sedimentary layers best implies that a) land plants are older than land animals. b) vertebrates and invertebrates evolved together. c) invertebrates lived on earth before vertebrates. d) land animals evolved at the same time as marine animals

answer: c). invertebrates lived on earth before vertebrates.

the invertebrates are the organisms which lack a particular vertebral column. these animals were living in aquatic habitat undergone a series of adaptations in the course of evolution. they increased the range of habitat from aquatic to land. these invertebrates undergone several adaptations to transform into vertebrate organisms which have proper vertebral column. the development of features from invertebrates to vertebrate transformation can be observed in fossils found in sedimentary layers.

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;