Activation energy is needed by a system to initiate a process.
The answer is b. For example, nuclear fusion in the sun (an exergonic process) releases energy as light and heat, and powers the initial steps of photosynthesis (an endergonic process).
The answer is Arachnids.
Crustaceans, Insects, and Arachnids belong to the phylum Arthropoda.
Of mentioned characteristics, most of the Insects have both wings and antennae. Remember all butterfly, bees, beetles, etc. Crustaceans (crabs, lobsters, shrimp, etc) have antennae, but they have no wings.
Thus, the only group of the mentioned that shows <span>neither wings nor antennae is Arachnids. Arachnids include scorpions, spiders, ticks, etc. and as it is known, these groups have neither </span><span>wings nor antennae.</span>
The substance is a compound because it's formed by two different elements.
