Q: Land could not be colonized by other organisms until what became established? Choices: - gases - carbon dioxide - oxygen - plants A:
plants

(Question)
Q: What type of galaxies have a rotating disk of stars and dust, a bulge in the middle, and several arms? Choices: - pinwheel galaxies - round galaxies - spherical galaxies - spiral galaxies A:
(Answer)
spiral galaxies

Ques: Q: Oxygen has the second highest electronegativity of any element; consequently, it prefers to share or accept electrons from other elements. only with fluorine does oxygen form compounds in this? Choices: - liquid oxidation states - chemical oxidation states - negative Oxidation States - positive oxidation states A:
Ans: positive oxidation states

(Q).
Q: The core of a star collapses during what event, forming a neutron star? Choices: - spark - blast - gravitational - supernova A:
(A).
supernova

Ques:Q: All atoms of the same element share the same number of what type of particle? Choices: - quarks - neutrons - nucleus - protons A:

Ans:protons

Q: What makes toenails and fingernails hard? Choices: - guanine - cellulose - taurine - keratin A:
keratin