What is about true about these atoms calcium, gold, argon, iodine

In moon rock sample the ratio of the number of stable argon-40 atoms present to the number of radioactive potassium−40 atoms is 7:1. Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of 2.5×10^9yr. The age of the rock is

Explanation:

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answer: after carbon dioxide enters the leaf through stomata it moves into the mesophyll cells where photosynthesis occurs and glucose is constructed. respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.

explanation:

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.