Gram-negative bacteria are sometimes problematic to kill with antimicrobial chemicals because Group of answer choices the chemical has a hard time crossing bacterial outer membrane. their surface is negatively charged. they grow slower compared to G( ) bacteria. their LPS is long and spiky. they are larger than G( ) bacteria.

Acommon kind of mechanical weathering is called

Why do we perceive objects as retaining their brightness under different lighting levels?

8) animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. d) a dog is getting hot in the sunlight, so he moves to a shaded area.