In which of the following situations will helper T cells be activated? when an antigen is displayed by a macrophage that engulfed a pathogen

when a cytotoxic T cell releases cytokines

when cytotoxic T cells come in contact with a tumor cell

when B cells respond to T-independent antigens

here is the answer

water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. weathering is the breaking down or dissolving of rocks and minerals on earths surface. once a rock has been broken down, a process called erosion transports the bits of rock and minerals away.