Which type of force requires contact between two objects for one to push or pull the other

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy

If the coding part of an mrna molecule is 1800 nucleotides (bases) in length, this molecule will contain codons and code for a polypeptide that is amino acids long.

How are the reproductive cycles of a fungus and a pteridophyte similar? a)both organisms form fruiting bodies that produce diploid seeds. b)both organisms produce haploid spores and exhibit diploid and haploid stages. c)both organisms reproduce sexually when two haploid hyphae fuse. d)both organisms exhibit a diploid stage and are only able to reproduce asexually.