Answer and Explanation:
Observing population directly gives you accurate result .
Direct observation does not need any intermediary as they themselves go for survey.
So, it is cost efficient.
Whereas indirect observing may involve manipulations.
It requires someone or many to hire who helps in surveying.
It incurs cost.
Thus, direct observation is always better than indirect observation.
Answer:
red will be the bottom layer
Explanation:
in order to find its density you have to do mass/volume.
Blue: 12/3 = 3
Clear: 10/5= 2
Red: 15/3= 5
Yellow: 18/9 = 2
The one with the greates valua aka greatest density will be at the bottom layer/
Phytoplankton are essential to aquatic life zones because: they provide the basis of food chains. Log in for more information. Added 5/22/2016 9:52:12 AM This answer has been confirmed as correct and helpful.
Answer:
The cilia is one of the things that act defensively in the respiratory system.
Explanation:
It propels a mucus-like liquid that covers the airway which traps pathogens (potentially infectious microorganisms) and other particles, preventing them from reaching the lungs.
