Radioactive materials decay by a first-order process. The rate constant for the decay of an isotope whose half-life is 7.69 years is​

k = 0.0901 yrs⁻¹

Explanation:

1st order decay is defined by the equation A = A₀e^-k·t. If A = A₀/2 and t represents the 1st half-life of the isotope then ...  

t(1/2) = ln2/k = 0.693/k => k = 0.693/t(1/2) = 0.693/7.69yrs = 0.0901 yrs⁻¹

water   molecules stay close to each other through cohesion, the collective action of hydrogen bonds between water molecules. cohesion plants draw water upwards from the root through the stem's transport tubes (xylem) to the leaf. this transport occurs even in large trees and against gravity. transpiration, evaporation of water from plant leaves, creates a tension on water molecules being pulled up from the stem and roots.

water also has high (the attraction of one substance to another) properties because of its polar nature. adhesion of water molecules to plant cell walls counteract gravity while water is transported from roots to leaves.

water exhibits a very high surface tension when compared to other liquids. surface tension is a property of a liquid that holds the surface together and allows it to resist an external force. by capillary action, the water forms concave menisci inside the pores. the high surface tension of water pulls the concavity outwards, generating enough force to lift water from the roots to the leaves of plants.

thus, cohesion, along with adhesion and surface tension creates a capillary action that keeps water molecules interacting and moving through the plants out to the leaf cells.

therefore, option d) is the correct answer.

explanation: