Which are examples of negative feedback? check all that apply

Hello. This question is incomplete. The full question is:

"Which are examples of negative feedback? Check all that apply.

A child whose thymus gland is building an immune system that gets stronger each day . When someone's adrenal gland reacts to a scary movie by secreting hormones that make the heart beat quickly . When someone's pancreas stops producing the hormone that lowers blood sugar because the person hasn't eaten recently . When someone's pancreas hormone increases every time they eat, but decreases when they aren't eating . When a person takes calcium supplements so a gland will stop secreting a hormone that pulls calcium from the bones."

Explanation:

Negative feedback is the most well-known mechanism and is directly linked to homeostasis. Most hormone secretions are regulated in this way. It is characterized by being a mechanism that reduces a certain stimulus, reversing the direction of change.

Examples of negative feedback are:

electromagnetic waves travel through space with vacuums. give me brainliest if right.

i guess it’s a and b