When does crossing over occur? how many chromatids are involved? how many homologous chromosomes?

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Which of the following particles always has a positive charge? a. electronb. neutron c. proton d. ion

Benito is doing research on the effects of florida's elevation on its climate. his notes include the following: 1. the average elevation of florida is 30 m above sea level. 2. the highest point in florida is britton hill, which is 105 m above sea level. 3. the change in temperature from 0 m to 1,000 m is 7 °c. what can benito conclude about the effects of florida's elevation on its climate? a.) florida typically experiences cold temperatures and temperature changes within a narrow range. b.) florida typically experiences cold temperatures and temperature changes within a broad range. c.) florida typically experiences warm temperatures and temperature changes within a narrow range. d.) florida typically experiences warm temperatures and temperature changes within a broad range.