Scientists think that algae first evolved approximately 2.7 billion years ago, and soon after this oxygen began to exist in the atmosphere. Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.
Explanation:
Answer:
1) ustedes son
2) nosotros somos
3) tu eres
4) ellos son
5) yo soy
6) nosotras somos
7) ella es
8) el es
9) ellas son
10) ustedes son
Explanation:
This should be right, unless you're using "vosotros".
Atoms are the basic units of matter. Protons are found in the nucleus of an atom and it has a positive charge.
Puedes ser mas especifico?
Answer:
no entiendo lo que me estas preguntando, lo podrias hacer mas claro?
Explanation:
