Sodium-25 after 3 minutes : 1.0625 mg
<h3>Further explanation</h3>
General formulas used in decay:

T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
<h3 />
No=8 mg
t1/2=60 s
T=3 min=180 s

Answer:
Mason notices that his boat sinks lower into the water in a freshwater lake than in the ocean. What could explain this?
Explanation:
The freshwater has less density then the ocean!
The density of a material is an intensive property.
<h3>
What is intensive property?</h3>
An intensive property of matter is one that does not change with the amount of matter. It is a bulk property, which means that it is a physical property that is independent of sample size or mass. An extensive property, on the other hand, is one that is affected by sample size.
<h3>What factors influence an intensive property?</h3>
Intensive properties are those that are determined solely by the characteristics of the material and not by its quantity - for example, density, temperature, refractive index, color, and pressure. Intensive properties are not additive, which means their value does not change when the amount of material is changed.
Learn more about the intensive property here:-
brainly.com/question/24909279
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Answer:
Scientific investigation aims to design and implement an experiment to learn new information, where
development aims to design a product to solve a problem.
Explanation:
The moon used to be connected with Earth. A meteor hit several billion years ago and split the Earth and Moon apart. This explains why they share the Sam properties.