Which of the following has a knot of nerve tissue at its head end?

a.

octopus.

b.

sponges.

c.

worms.

d.

bacteria.

At about what age do children usuallt begin to say words

What is an individual who carries two different alleles of a gene is termed?

How do invasive species harm ecosystems?

How did oxygen first enter Earth's atmosphere

The process of active transport requires the most direct use of

In frogs muscle tissue is usually grouped into large

after the brain receives information from the body's sensory receptors, what is the next step in responding to this information?

What does the endosymbiont theory explain about the origins of plant and animal cell

Suppose you have monohybrid pea plants in your garden and find that they produce round seeds to wrinkled seeds in the ratio of 3:1 if the alleles are designated R and r, respectively, what are the probable genotypes of the wrinkled seeds produced by

What is the average for the following measurements 7.1 g, 9.8g, 2.3g, 8.5g, 7.4g, 5.7g