What is a role of the pacemaker or sinoatrial node (SAN) ?

A. To initiate contraction of the ventricle

B. To pass the excitation through Purkinje fibres

C. To originate excitation in myogenic muscle

D. To cause the relaxation of the atria

Sort the following fungi based on whether they are decomposers, mutualists, or parasites.

Imagine that a taxonomist is provided with several flashcards on which the names of different species are written. She would likely organize these flashcards to construct a phylogenetic tree.

Claudio is out on a whale watching boat trip. He sees a dolphin near the boat because light waves pass through the structures of his eye. Which step of processing in the visual system does this describe? a. step 1: physical stimulus b.

What two factors of a molecule determine whether or not it can cross the membrane

I'll put you as brainliest Which of the following best describes the influence carrying capacity has on the growth rate of populations?

A mother sleeping in the middle of the night nevertheless responds when she hears her 2-year-old daughter crying in the adjacent bedroom. This indicates that the mother possesses:

How can farmers keep topsoil on their land? check all that apply. a. close their gates b. keep plants growing c. plant trees to shield fields from the wind d. do not plow when extremely heavy rains are expected?

Measures how much matter is present in a substance

How is artificial selection similar to natural selection?

Which of these is a distinguishing characteristic of terrestrial habitats? O A. Plant life O B. Presence of oxygen O C. Salinity levels O D. Human presence