A hiker finds a smooth, rounded pebble along the shore of a stream that is flowing down from a mountain. Which of these most likely caused the pebble to have this appearance?

A, b,c or d !?
PLS I NEED HELP

Which best describes a rhinovirus? o a. a virus that causes a common cold o b. a protective shell around a virus o c. a tube the comes off a virus o d. a piece of dna transferred by a virus

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

Which part of the neuron below is indicated by the arrow, and what is its function? hormones send chemical signals throughout the body to regulate other body processes. hormones are chemical signals that are sent throughout the body to regulate other body processes. hormones send electrical signals throughout the body to regulate other body processes. hormones are electrical signals that are sent throughout the body to regulate other body processes.