1. the movements of energy and nutrients through living systems are different because (1 point)
energy flows in one direction, and nutrients recycle.
energy is limited in the biosphere, and nutrients are always available.
nutrients flow in one direction, and energy recycles.
energy forms chemical compounds, and nutrients are lost as heat.

2. which of the following depends on bacteria? (1 point)
conversion of dead organic matter to fossil fuel
photosynthesis
dissolution of phosphates from rock
nitrogen fixation

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.

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?