A boat travels upstream from Q to P and downstream from p to Q in 3 h. If the distance between P to Q is 4 km and the speed of the current is 1 km/h , then what is the speed of the boat in still water?

#Question id: 12013

#Unit 10. Ecological Principles

The average daily temperature change on an exposed south-facing slope and a north-facing slope for a late summer day in the Northern Hemisphere are shown below.

The difference in the  maximum average daily  temperature between the  south-facing slope  and  the  north-facing slope is approximately

#Question id: 10165

#Unit 6. System Physiology – Plant

In the C4 photosynthetic carbon cycle involves uptake of CO2 in the form of HCO₃^-, the acceptor of the HCO₃^- is

#Question id: 4579

#Unit 11. Evolution and Behavior

About which of these did Darwin have a poor understanding?

#Question id: 5682

#Unit 5. Developmental Biology

During prevention of polyspermy in sea urchin the shift from ___1___ to __2____is the result of a small influx of Na+ into the egg through newly opened sodium channels. Sperm cannot fuse with egg cell membranes that have a ___3___ resting potential, so the shift means that no more sperm can fuse to the egg.

#Question id: 19687

#Unit 13. Methods in Biology