Carbon and hydrogen are present in all
nitrogen is common
sulphur in proteins is common
oxygen is common in ethanoic acids
phosphorus is common for phosphate sugars
hope that helps
The amount left after 20 years = 154.15 mg
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles
The decay formula for isotope :

Then for t=20 years, the amount left :

Can you give more information?
Biodiversity has a fundamental value to humans because we are so dependent on it for our cultural, economic, and environmental well-being. Some argue that it is our moral responsibility to preserve the Earth’s incredible diversity for the next generation. Others simply like knowing that nature’s great diversity exists and that the opportunity to utilize it later, if need be, is secure. Scientists value biodiversity because it offers clues about natural systems that we are still trying to understand. Arguably, the greatest value to humans, however, comes from the ?ecosystem services? it provides.
Biodiversity forms the backbone of viable ecosystems on which we depend on for basic necessities, security, and health. By breaking down plant and animal matter, for example, insects and other invertebrates make nutrients available to plants and are integral to the carbon and nitrogen cycles. Other species pollinate crops, an essential service for farmers. Healthy ecosystems can mitigate or prevent flooding, erosion, and other natural disasters. These ecosystem services also play a hand in the functioning of our climate and in both air and water quality.
CO2 and H2O are compounds hope this helped :)