A researcher notices a decline in organism and population numbers over several years in a stream environment. What human activity may have affected organisms and populations in this way?

Until the ___, scientists thought organic chemicals could only form by actions of living things. A.) Twenty-first century B.) 1980's C.) mid-1800's D.) none of the above

Which crops are harvested for biomass production?

In which plant cell organelle does photosynthesis take place

What kind of crystals halite crystal (rock salt) ? tetragonal orthorhomic monoclinic cubic

These items are involved in sexual reproduction. Which one of these may also be involved in asexual reproduction? A. Eggs B. Spores C. Sperm D. Seeds

Which of the following are found in plant cells but not animal cells? plastids ribosomes chloroplasts vacuoles

Which characteristic of the male reproductive system is not variable among animal species that reproduce sexually?

Why the children in a family may have different genotype and phenotype than predicted by the punnet squre

What is meant by the term "chemically gated sodium channel"? Group of answer choices A membrane channel that opens when some chemical binds to it, allowing sodium to cross the cell membrane A membrane channel that opens when sodium binds to it,

Scientists now know how much carbon dioxide was present in the atmosphere as far back as 800,000 years ago. How did they obtain this data?