The heart, liver, and stomach are each examples of

a. an organ.

b. a tissue.

c. a nerve.

d. an organ system.

What is the Morgan-Keenan Spectral Classification system? A method of classifying stars by their temperatures and compositions. A method of classifying stars by their distance from the Sun. A method of classifying stars by their age.

As described in Investigating Life 20.1, scientists found that the range of the alpine chipmunk has shifted about 500 meters up in elevation, leading to isolated subpopulations on individual mountaintops.

The musk ox has a large body size and small appendages. How do these characteristics enable it to survive in the tundra?

What produces the hormone that promotes maturation of t cells?

The primary function of the human male reproductive system is to (1) provide a site for fertilization (2) produce and transport gametes (3) protect and nourish the embryo (4) prevent urine from leaving the body

Which molecule is synthesized by plants and is a major source of energy for plants and animals?

A biology student wants to understand how blood flows through the aorta. To model the heart and aorta, she sets up two identical pressure-controlled tanks that push blood through a 2-centimeter diameter tube. Her results are shown in the table below.

Which characteristic should describe all evidence collected by a scientis

What macromolecule is the primary energy source for organisms?

What is the difference between diploid and haploid cells?