Can someone explain this pleaseee? Thank u

Which best describes a gene? a. a sister chromatid b. a chromosome c. a tetrad d. a piece of a chromosome

Which statement is the best summary of the model? a-a series of aerobic and anaerobic reactions take place in cells b- the sun's energy moves through trophic levels in a food chain c-light energy is converted into stored chemical energy plants.d- food molecules are broken down in the cells if living things.

In which squares should the phrase "green pods" appear a) a and d b) b and e c)a,c, and d d)a,b,c,d and e