The correct answer is - D) covered by warm shallow seas.
The fact that the crinoids are have an abundance in the fossil records in Pennsylvania in the Mississippian Period, tells us that this area was covered with shallow and warm seas. The reason why we can get that conclusion is that the crinoids live only in that kind of environment, so it simply a logical conclusion.
The geological data is also confirming this, as it is easily noticeable in the layers that during this period of the geologic past, what is now Pennsylvania, was covered with shallow sea waters. Also, this waters were warm too, as the climate was warm and humid and that period, so it was a perfect environment for the crinoids to flourish.
The answer is B Have a great day sweetie
Answer:
unicellular life first
Explanation:
it arose billions of years ago while multicellular life forms around at least 600 million years ago
The number of phenotypes produced for a given trait depends on how many genes control the trait. Anyhow, The distribution of phenotypes for a typical polygenic trait can often be expressed as a bell-shaped curve.
Many traits are controlled by two or more genes and are, therefore, called polygenic traits<span>. Each gene of a polygenic trait often has two or more alleles. As a result, one polygenic trait can have many possible genotypes and phenotypes.</span>
Agriculture depends on the conservation of our most precious natural resources: <em>water, land, and biodiversity.</em>
