A new species of chordate is discovered. It produces a free-swimming larva that has a notochord and a nerve cord. The larva attaches to a surface and matures into a saclike adult that filter feeds. The notochord and nerve cord are not present in the adult. To what group of chordates does this new species belong?

echinoderms
jawless fish
lancelets
tunicates

a lot of people sadly don't know the best way to learn is cheating off of your friends or this amazing thing called google

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

propane is burned to provide the heat in many cooking grills. the chemical reaction for this process is shown in the equation below.

c3h8 + 5o2 ? 3 co2 + 4h2o + energy

what are the products in this chemical reaction?

3co2 + 4h2o + energy