The ras proto-oncogene can become an oncogene by a single point mutation that alters its protein product to have activity.
a. more gtpase
b. less nucleotide exchange
c. greater nucleotide exchange
d. constitutive raf-activation

The correct answer is D.

Explanation:

The Ras Proto-Oncogene is a gene found in normal cells, which by the single point mutation mentioned in the question, can turn into Oncogene. Because Proto-Oncogene is a gene that controls and regulates the division of the cell, a mutation in this gene leads to uncontrolled cell divisions which then leads to cancer. The correct answer is D since RAF-Activation describes "Rapidly Accelerated Fibrosarcoma, fibrosarcoma being a cancer which affects fibrobalst cells.

I hope this answer helps.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

ι вєℓινє тнє αиѕωєя тσ уσυя qυєѕтισи ιѕ в. ℓуѕσѕσмє

ι нσρє тнαт ι ¢συℓ∂ нєℓρ уσυ.