An organism's development from an embryo may contain clues about its history that scientists can use to develop relationships and build evolutionary trees. ancestral characters are often preserved in an organism's developmental stages. for example, both bird and human embryos go through a stage where they have slits and arches in their necks like the gill slits and gill arches of fish. these structures are not gills and do not develop into gills in birds and humans, but because they are so similar to gill structures in fish at this point in development scientists believe that
a) birds and humans evolved from fish.
b) all vertebrate animals have identical embryos.

c) fish, birds, and humans share a common ancestor.
d) fish evolved as a life form long before birds or humans.

Select all that apply genes are specific nucleotide sequences occur in numbers that are the same as the number of chromosomes are located in a specific place on a chromosome determine the traits of an organism are units of rna

Explain the cellular functions that occur when antibiotics attack a bacteria cell. a. antibiotics target the cell wall, cell membrane, and the processes of protein and nucleic acids production in bacteria to rupture the cell. b. antibiotics create dormant resistant endospores to preserve the genetic material and rupture the cell. c. antibiotics target the cell wall and form a bridge-like connection to form conjugation. d. antibiotics use binary fission to grow twice its size, replications its dna, and split into two cells.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.