Answer:
I believe you're missing the decomposers
Explanation:
Answer:
B. They are among the most productive types of ecosystems.
Explanation:
The estuaries provide migratory birds a place to rest. for example.
Answer:
Some pathogens are transmitted by a single route and others by several, the more transmission routes are recorded, the more pathogens they are, in the HIV virus the transmission is vertical and horizontal therefore it has high pathogenicity, on the other hand, the varicella virus is transmitted only by inhalation.
Explanation:
The vertical route is the transmission through childbirth, it is the moment in which the mother contacts the child's blood and transmits the virus, nowadays the vertical contagion of HIV is highly controlled.
On the other hand, the horizontal route is also called parenteral, it is one that consists of the inoculation of the virus through uncontrolled blood transfusions, intravenous drug addiction by syringe compartment, or uncontrolled injections.
A
Hope this helps and works out
Answer:
2%
Explanation:
The scientist believe that around 2% of the species that existed on Earth have been preserved in the fossil records. It is still a hot debate about it though, as there are only around 250,000 species identified in the fossil records so far, which is less than a quarter from the species that live in the present.
The reason why scientists believe that the majority of the species have not been preserved are very logical though. One of the reasons is that lot of species existed very long time ago, so their remains just didn't lasted so long. Other reason is the movement of the plates, where we have situation where plates that existed in the past have been totally suducted and melted in the mantle, while others are at the verge of it, so every fossil with them is melted and destroyed too. Another reason is that lot of species do not have hard parts, solid bone structure, so their preservation has been pretty much impossible,