Which of these is a segment of dna that contains information necessary to produce a protein? a. a base b. a gene c. a codon d. a chromosome

How does friction with the atmosphere affect the speed of an artificial satellite

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is most likely effect on the ecosystem?

Which statements about a food chain are true? choose all answers that are correct. a.plants are the first living organisms in food chains on land. b. the plants in a food chain are called herbivores. c. all food chains on land begin with energy from the sun. d. carnivores in a food chain eat only plants.