The cell membrane is a protective external layer that controls which substances are allowed to enter and leave the cell. The
cell membrane performs the same function in the cell as which
structure in the human body?
Blood
Skeleton
Skin
Hair

Most scientific questions are based on opinions. hypotheses. observations. experimental data.

The construction of phylogenetic trees is a mapping out the proposed divisions and common ancestors of all living species. traditionally, these trees have been built using morphological data, such as appearance and embryology. recently, it has been possible to construct these trees using molecular data. phylogenetic trees based on different types of information agree with each: that there is strong evidence of a real underlying common descent. this phylogenic tree is composed based on molecular data (rrna). what statements can we infer are true about the organisms throughout the tree? because the tree is rooted, all branches share a common ancestor. all organisms have some sort of cellular structure/organization. all eukaryotes evolved from bacteria. since the organisms contain rna, they share the same dna. if the organisms contain rna, the share the same four nitrogen bases.

The study of interaction between living organisms and their enviroment is called (a) phytogeography (b) ecology (c) phytosociology (d) ecosystem