Which of the following are clues that a chemical reaction may have taken place?

a. temperature remains constant

b. release of heat

c. formation of a solid

d. mass increase

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

On mars a rock falls an unknown vertical distance from a resting position and lands in a crater. if it takes the rock 2.5 seconds to fall, how high is the cliff the rock fell from? mars' surface gravity is 3.8 m/s2.

Answer asap 50 points which of the following illustrates how a venus fly trap senses that an insect has landed in its open leaves? 1. using tiny hairs, the leaves sense a change in light. 2. using tiny hairs, the leaves taste a chemical. 3. using tiny hairs, the leaves detect a touch. 4. using tiny hairs, the leaves sense a change in water levels.