3 different difficulties scientists will face when solving we protect the arctic habitat of polar bears from climate change?

Sand spinifex grass is adapted to growing on sand dunes. it is a rapidly spreading plant and the creeping runners produce new root systems. which of these best explains the benefits of these features? a. it limits water loss through the leaves. b. it provides support by anchoring the plant. c. it protects the plant from predators. d. it allows the plant to tolerate salt. reset submit

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

Hurry where is the majority of earth's water found? o glaciers o oceans ground o rivers and lakes