17. a
18. c
19. a
20. c
21. c
Answer:Mechanical ventilation system
Explanation:
Ventilation can be increased to safe levels by using mechanical ventilation system to bring in more fresh air.
There are many ways to provide ventilation for example
- providing ventilation fans in kitchens and bathrooms to remove allergens,moisture.
- A duct should be provided such that it provides fresh air to different rooms and provision should also be made to remove the poor air inside home.
Explanation:
c) is equal to the momentum of the fired bullet
As to why decomposers are important in the carbon and nitrogen cycles, well, they are. Decomposers, as their name strongly suggests, decompose matter, more specifically dead matter and waste materials. These decomposers break down the dead body of the once-living organisms and the living organisms' waste materials to their basic state. While in the process, the carbon is released as carbon dioxide. Nitrogen is also released in the process. Either they are both released into the atmosphere or are trapped on the ground. Some dead matters don't undergo decomposition due to certain factors which leads them to become fossil fuels and their compositions are released through human activities.
