The mass extinctions that occurred 250 million years ago and 65 million years ago may have been due to gradual process or?

What is upwelling and why is it important?

Explain why the marine ecosystem generates a significant fraction of the oxygen in the atmosphere. A) The marine ecosystem generates 32% of the world's primary producers.

Give an example of how energy from the sun gets into your cells

Which of the following is flagellated cell which sweeps water through a sponge's body? a. choanocyte b. ameobocyte c. archaeocyte d. neuron e. chondrocyten

Punnett squares show phenotypes, from which genotypes can be determined. True False

The doctor said "The child is you, simply the best of you." What does this mean?

2. What is an investigation? What is a demonstration? How are the different?

In animals, embryonic stem cells differ from adult stem cells in that

Which are the two primary limiting nutrients for plant growth?

Sorry but i was asking for one of the credit card to pay for ca