NEED HELP! Sickle cell disease is lethal, usually killing its victims before they reach maturity and can reproduce. According to the theory of natural selection, the sickle cell gene should not remain in the population. How do scientists explain its prevalence in certain regions?​

Which of the following is not a classification of marine organisms? a. benthos c. neritic b. nekton d. plankton select the best answer from the choices provided a b c d i know the answer is not option b

Select the correct answer from each drop-down menu. during the day, plants produce by splitting water molecules in the light-dependent reactions of photosynthesis. at the same time, plants use cellular respiration to produce some of the needed by the light-independent reactions to make sugars. during the night, plants produce because takes place.

Ineed to get this test done which of the following statements is correct in hour our immune system responds to a potential pathogen? a.) the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. b.) b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c.) the adapted immune system will call on the innate immune system to destroy the pathogen. d.) the t-cells in the adapted immune systems are the first to recognize the pathogen