Two radioactive nuclei A and B are present in equal numbers to begin with. Three days later, there are 2.44 times as many A nuclei as there are B nuclei. The half-life of species B is 1.14 days. Find the half-life of species A (in days).

Suppose you are estimating the size of a blue crab population. what is the population size if the number marked in the first catch is 40, the total number in the second catch is 200, and the number marked in the second catch is 50?

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

What is the primary goal of human communities?