What must be true for any endothermic reaction?

a. the chemical bonds of the products have more energy than the chemical bonds of the reactants.
b. there are more products than there are reactants.
c. there must be a phase change from solid to liquid or from liquid to gas.
d. the reaction must take place in a sealed container held at constant volume.

Answer : The correct option is, (a) The chemical bonds of the products have more energy than the chemical bonds of the reactants.

Explanation :

Endothermic reaction : It is defined as the chemical reaction in which the energy is absorbed from the surrounding.

In the endothermic reaction, the energy of reactant are less than the energy of product.

Exothermic reaction : It is defined as the chemical reaction in which the energy is released into the surrounding.

In the exothermic reaction, the energy of reactant are more than the energy of product.

Hence, the correct option is, (a) The chemical bonds of the products have more energy than the chemical bonds of the reactants.

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)