Why do pigeons have heart shaped ceres on their nostrils

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.

Your two friends just told you what to order for them at the drive through fast food restaurant. you give the order but when the food comes about 10 minutes later, you don't remember what each of your friends ordered your memory of the order was in __ memory. a. semantic b. flashbulb c. long-term d. short-term i think i know but i'm not really sure

Suppose you are provided with an actively dividing culture of e. coli bacteria to which radioactive thymine has been added. what would happen if a cell replicates once in the presence of this radioactive base?