Is energy required for substances to pass in or out of the cell?

What best explains the inability for life to exist in earth early atmosphere

Areal dna molecule consists of thousands of these pairs of nucleotides. what is the pairing arrangement of the nitrogen bases

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?