Down syndrome is the result of an extra chromosome 21 in a gamete. What caused this to happen?

nondisjunction

telomeres

environment

chromosome inactivation

Drag the tiles to the correct boxes to complete the pairs. match the nitrogenous base of dna with its complement.

The earth's oceans are made up of chlorine, and trace elements. a) carbon, oxygen b) oxygen, silicon c) hydrogen, oxygen d) nitrogen, oxygen

Imagine a person stepping on a pin and pulling his or her foot away. look at the reflex arc of this scenario below. which statement best describes the image? a)the sensory nerve carries the signal from the effector to the interneuron, and the motor neuron carries the signal to the receptor. b)the motor nerve carries the signal from the receptor to the interneuron, and the sensory neuron carries the signal to the effector. c)the sensory nerve carries the signal from the receptor to the interneuron, and the motor neuron carries the signal to the effector. d)the sensory nerve carries the signal from the receptor to the motor neuron, and the interneuron carries the signal to the effector.