Environmental factors can influence natural selection because they can increase or decrease O the number of chromosomes in an individual.
O the number of chromosomes in a population.
the amount of genetic variation in an individual.
the amount of genetic variation in a population.

Last week i was assigned a thematic. we have groups of three but the people i was assigned with haven't been in school for days. i would appreciate if anyone can me with my thematic . i highlighted most of the important steps and i circled my thematic topic. in desperate need : ( its due on february 19

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

Below are the three main organs that make up the plant body. what is the main function of the structure that is identified as b in the picture above? it anchors the plant.it produces food.it absorbs nutrients.it supports the plan