Scientists rely on concepts when researching crop production and medicine.

(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.

All phases of matter may have a fixed mass

Which of the following molecules could pass through the plasma membrane by simple diffusion? a. na+ ions b. glucose c. amino acids d. carbon dioxide