at what point in sperm production do you hypothesize that loss of the testis-blood barrier would have an immunological effect on sperm production?

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.

How do high-energy electrons from glycolysis and the krebs cycle contribute to the formation of atp from adp in the electron transport chain? a. high-energy electrons interact with pyruvic acid to create a phosphate bond with adp, forming atp. b. high-energy electrons supply the needed energy to synthesize atp from the lower-energy adp in the electron transport chain. c. high-energy electrons supply a negative charge which causes the citric acid to oxidize, forming a phosphate group to bond with adp. d. high-energy electrons increase the temperature of adp so it easily reacts to form atp.

Some jellyfish have skeletons that are formed by fluid-filled compartments. this fluid resists compression and thus supports the body structure from deforming. which term describes these skeletons? a. fluid skeletons b. hydrostatic skeletons c. exoskeleton d. endoskeleton