The Cambrian Explosion is when diverse animals were first recorded as fossils.
Answer:
B. Enough trees to create a close canopy.
Explanation:
Forests may have several tree species but one very important feature of forests is their close canopy of dense trees, often arranged in several strata (or layers).
Water is a polar molecule because its opposite ends have opposite electric charges.
Answer:
DNA is also called deoxyribonucleic acid which is made up of two chains which wind around each other to form a double helix model. The 2 DNA strands are also called polynucleotides and they are made up of monomeric units known as nucleotides. These nucleotides are made up of one of four nitrogen-containing nucleobases: cytosine, guanine, adenine and thymine, a phosphate group, and sugar known as deoxyribose.
Nitrogen bases present on the two separate polynucleotides strands are bound together with the help of base pairing (such as adenine with Thymine) and with hydrogen bonds to form double-stranded DNA.
So, adenine in DNA is complementary to thymine.
