Please help me I’m so not smart.

Individuals who live below the poverty line get seriously ill more often than those who do not what could be the hidden variable in this situation?

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.

Atoms seldom exist as independent particles in nature a) as single particles, most atoms have low potential energy b) their electronegativity is much lower when they combine with other atoms c) atoms are more stable when they combine with other atoms d) neutral particles are rare