Brainlies ! 1. a student made the following observations about astronomical bodies. observation 1: mars reverses its direction of motion in the night's sky. observation 2: the stars move across the sky. which observation(s) can be explained using the heliocentric model but not the geocentric model? only observation 1 only observation 2 both observation 1 and observation 2 neither observation 1 nor observation 2 2. the following table shows the duration of a year on some unknown planets of equal mass. duration of year planet duration of year y 224 days z 320 days which of the following best explains which planet is closer to the sun? planet y, because gravity is directly proportional to square of distance planet z, because gravity is directly proportional to the square of distance planet z, because the sun exerts a greater gravitational force on it than on planet y planet y, because the sun exerts a greater gravitational force on it than on planet z

1 - both can be proved by the heliocentric model since it is the currently most accepted theory.

2 - since planet y has a lower planet duration year, it means it is closer and the sun exerts a higher gravitational attraction making it spin faster therefore completing the year (equivalent to one spin around the sun) in less time.

Hope it helped,

Happy homework/ study/ exam!

answer; ///(b) it is composed of four protein chains and four heme groups;

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.