Why might a scientist use a physical model of a plant cell instead of studying a cell directly?
OA. A model can be used for things that are too simple to study
O B. A model can be used for things that are too hot to handle easily.
O C. A model can be used for things that are too large to study directly.
OD. A model can be used for things that are too small to see clearly.
directly.

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

Astudent pushes on a 20.0 kg box with a force of 50 n at an angle of 30° below the horizontal. the box accelerates at a rate of 0.5 m/s2 across a horizontal floor. what is the value of the normal force on the box? 200 n 243 n 156 n 225 n

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?