DDT is an insecticide that was used extensively in the mid-1900s to kill mosquitoes. It was very effective at first, but after a few decades DDT became less effective at killing mosquitos because many populations has evolved resistance to DDT. Which of the following conditions would biologists say was required for the evolution of DDT resistance in a population? A) A few mosquitos in the population were resistant to DDT before it was ever used.
B) Mosquitoes in the population learned to adapt to the high levels of DDT in the environment.
C) The mosquitos population needed to evolve DDT resistance in order to avoid extinction.
D) Exposure to DDT caused specific, nonrandom mutations for DDT resistance within the population.

Ry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached? gene flow greatly affects small populations, but large populations can recover. genetic drift greatly affects small populations, but large populations can recover. gene flow greatly affects large populations, but small populations can recover. genetic drift greatly affects large populations, but small populations can recover.

Which of the following is the best definition for the process of photosynthesis? a.) plants digest sugars to make energy. b.) plants use oxygen and glucose to make carbon dioxide. c.) plants use sunlight and carbon dioxide to make sugars. d.) plants use sunlight to make chlorophyll and chloroplasts.

Give three examples of plant activities that are affected by circadian rhythms and natural fluctuations in the length of daylight?