What would cause producers in some ecosystems to not make an unlimited supply of organic material

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

Which statement is not an accurate description of meiosis? a) meiosis produces offspring that are genetically diverse. b) meiosis produces offspring that are identical to the parent. c) in sexual reproduction half of the genetic material comes from the father (sperm) and half of the genetic material comes from the mother (egg). d) meiosis decreases the number of chromosomes by half so that when a sperm fertilizes an egg, the resulting zygote has the correct number of chromosomes.