Considering natural resources (i. e. food, water, space) are limited, which of the following is true regarding organisms?
a. All organisms must develop new diets to exist.
b. All organisms face a constant struggle for survival.
c. All organisms display vestigial structures.
d. All organisms have a species half-life.

Which best explains how this maneuver unblock a person's airway?

Are the earth's ocean floor and continents the same age geologically? why or why not?

20 point pls brianliest 1. what does a red shift mean? blue shift? 2. describe the big bang theory. according to this theory, how old is the universe? 3. scientists believe the universe is expanding. what is the evidence that supports this? 4. describe a nebula. 5. describe the 3 types of galaxies. what is a barred spiral galaxy? 6. what is a light year? how far is alpha centauri from earth? 7. describe the universal law of gravitation. be sure to include gravitational force between two objects. 8. describe the planets’ orbits around the sun. 9. what is the asteroid belt? where is it located? 10. describe rotation and revolution of earth. what determines an earth day and year? 11. how do galaxies exist? 12. compare and contrast the inner and outer planets. 13. what causes the seasons?