What is the layer of soil in polar tundra that is always frozen is called

Select the correct answer from each drop-down menu. in an experiment, dr. travis examined the effects of calcium intake on osteoporosis, a condition that causes an increased risk of bone fractures. the amount of calcium is variable. the risk of bone fractures .

Describe the two types of vascular tissue

Northern switzerland has a fairly cold climate caused by sea winds from the atlantic ocean but souther switzerland tends to be much warmer and sunnier, what could cause this difference?