Scientist believe that the first life form appeared over how many years ago

Which chamber receives blood from all the body veins

Malfunctions of the mitochondria can cause a number of disorders. Which statement best explains how mitochondrial problems can affect an organism?

Which transports digested lipids and bile across digestive fluids to the surface of mucosal cells? a. LDL'sb. micellesc. HDL'sd. chylomicrons

How is carbon dioxide exchanged between the biosphere and the atmosphere?

Mid-ocean ridges are segmented and contain which two basic types of plate boundaries linked together?

How are objects placed in space? a. in random pattern b. in a rigid pattern c. in a loose pattern d. in no pattern

Explain the concept of natural selection.

A cell has the following features; a nucleus, mitochondria, ribosomes, a cell wall made of chiton and a cell membrane. What type of cell is described? A) animal B) bacteria C) fungi D) plant

The energy for the water cycle comes from the Sun. a. True b. False

Which tissue type is formed by many cells joining together, each contributing a nucleus? Select one: A. smooth muscle B. cardiac muscle C. dense regular D. skeletal muscle