Nitrogenous base, sugar and phosphate
DNA mutations that actually originate in the gametes is mainly responsible for genetic biodiversity existing in modern organisms. The term biodiversity actually refers to the variety as well as variability of life that is found on the planet earth. his variety can be seen between species, the ecosystem and within the species.<span />
Primary reinforcers have distinctive reinforcing qualities; not learned. In addition, secondary reinforcers has no inherent value and only has reinforcing qualities when linked with a primary reinforcers. The positive reinforcement is a desirable stimulus is added to increase behavior while negative reinforcement is an undesirable stimulus is removed to increase behavior.
Characteristics of Lancelets:
Small
Elongated
Marine invertebrate
Lacks a jaw
No sense organs
Has a notochord
Example: Lamprey
Characteristics of Tunicates:
Marine invertebrate
Has an outer coat that is rubbery or hard
Has two siphons
Examples: sea squirts, salps
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Answer:
2,787
Explanation:
Currently there are over 2,787 active artificial satellites orbiting the Earth.