1. light is the fastest-known entity in our universe.

true or false

2. there are fewer than one billion stars in the galaxy.

true or false

3. hydrogen atoms do not repel each other within a star.

true or false

4. sky maps show celestial spheres, including constellations.

true or false

5. which of h following happens during the main-sequence stage of a star's life?

a) it cycles, appearing brighter and dimmer in turns.

b) it changes the color that it emits.

c) it increases its distance from the sun.

d) it grows continuously smaller and dimmer.

What organs comprise the respiratory system of a bird

The image shows a group of fish. the type of social behavior shown in the image is called

Embryonic stem cells are cells derived from an embryo. these cells can be used to create new tissues for patients suffering from certain illnesses and disorders. which statement best summarizes why the use of embryonic stem cells could be seen as unethical? a. some people consider embryos to possess rights equal to those of fully developed human beings. b. extracting stem cells from embryos is a very energy-intensive process, which consumes resources that could be used elsewhere. c. embryos are difficult to obtain, so the monetary cost of using them for research outweighs their benefit. d. the process of extracting stem cells from embryos generates biohazardous waste that cannot be safely disposed of.