why does the plasma cell have a well developed endoplasmic reticulum with lots of ribosomes

What feature of cell theory is best demonstrated in the image

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?

Explain in your own words what caused pangea to separate and why we don't worry about earthquakes in florida.